| File extension | Developer/Producer | File description |
|---|---|---|
| C file extension | N/A | C/C++main Source Code File Format |
| C# file extension | Microsoft Corporation | Microsoft Visual C# |
| C++ file extension | Microsoft Corporation | C++ Source Code |
| C-- file extension | Barry Kauler | Sphinx C-- Language Source Code |
| C-MAP file extension | Jeppesen Marine, Inc. | C-map |
| C00 file extension | e-merge | Split Multi-volume ACE Compressed File Archive |
| C01 file extension | e-merge | Split Multi-volume ACE Compressed File Archive |
| C02 file extension | e-merge | Split Multi-volume ACE Compressed File Archive |
| C03 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C04 file extension | N/A | Split Multi-volume ACE Compressed File Archive |
| C05 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C06 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C07 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C08 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C09 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C1 file extension | Persistence of Vision Raytracer Pty. Ltd. | Pov-Ray For Windows 3.x Scenes Advanced Newltpot |
| C10 file extension | E-merge | Split Multi-volume ACE Compressed File Archive |
| C11 file extension | SINTEF | CARE-S InfoWorks User Defined Pollutant Detail |
| C16 file extension | CyberLife Technology Ltd. | C16 Creatures 3/Docking Station Image |
| C18 file extension | Dassault Systèmes S.A. | Dassault Systemes Catia V4 Sequential |
| C1S file extension | N/A | Photo Cache |
| C2 file extension | Persistence of Vision Raytracer Pty. Ltd. | Pov-Ray For Windows 3.x Scenes Advanced Newltpot |
| C21 file extension | SINTEF | CARE-S InfoWorks Defined Pollutant Detail |
| C24 file extension | PowerQuest | Drive Image Ace |
| C2C file extension | VSO-Software | CopyToDVD Project |
| C2D file extension | Roxio | WinOnCD Image Format |
| C2E file extension | NJStar Software Corp. | Chinese Dictionary Index |
| C2K file extension | Microsoft Corporation | Microsoft Project Holidays |
| C2R file extension | Microsoft | Microsoft Windows Media Center Click-to-record Format |
| C2U file extension | Texas Instruments | Texas Instruments CBL 2 Format |
| C2V file extension | WellSight Systems Inc. | WellSight Systems License Information |
| C2W file extension | Bentley Systems, Incorporated | WaterCAD |
| C2X file extension | N/A | WinOnCD |
| C3 file extension | Persistence of Vision Raytracer Pty. Ltd. | Pov-Ray For Windows 3.1 Scenes Advanced Newltpot |
| C32 file extension | Syslinux | Syslinux COM32 Module |
| C39 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C3D file extension | N/A | Coordinate 3D Format |
| C3D1 file extension | CambridgeSoft Corporation | Chem3D Cartesian 1 Chemical Modeller |
| C3D2 file extension | CambridgeSoft Corporation | Chem3D Cartesian 2 Chemical Modeller |
| C3E file extension | N/A | CYPE Related |
| C3T file extension | CambridgeSoft Corporation | Chemical Template |
| C3XML file extension | CambridgeSoft Corporation | Chem3D XML Format |
| C3Z file extension | OpenQwaq | OpenQwaq 3D Model Format |
| C4 file extension | JEDMICS | JEDMICS Bitmap Image Format |
| C40 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C41 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C42 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C43 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C44 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C45 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C46 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C47 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C48 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C49 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C4D file extension | Maxon | CINEMA 4D File Format |
| C4DUPDATE file extension | MAXON Computer GmbH | Cinema 4D Update |
| C4F file extension | RedWolf Design GmbH | Clonk Game Round |
| C4G file extension | RedWolf Design GmbH | Clonk Game System |
| C4K file extension | RedWolf Design | Clonk Key Format |
| C4P file extension | Codeweavers | CrossOver Software Installer Format |
| C4S file extension | RedWolf Design GmbH | Clonk Game Scenario |
| C4U file extension | Open Clonk Development team | OpenClonk Update System |
| C4V file extension | RedWolf Design GmbH | Clonk Game Video |
| C50 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C51 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C52 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C53 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C54 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C55 file extension | e-merge GmbH | Split Multi-volume ACE Compressed File Archive |
| C6 file extension | Ashlar Incorporated | Organic 2D/3D Drafting & 3D Modelling |
| C64 file extension | N/A | Commodore 64 ROM Image |
| C85 file extension | RISCOS Ltd. | RISC OS JPEG Bitmap Image |
| CA file extension | N/A | Telnet Server Initial Cache Data Format |
| CA1 file extension | Embarcadero Technologies, Inc. | Delphi Install Disk |
| CA2 file extension | Embarcadero Technologies, Inc. | Delphi Install Disk12 |
| CA4 file extension | Embarcadero Technologies, Inc. | Delphi Installation |
| CA5 file extension | Embarcadero Technologies, Inc. | Delphi Installation |
| CAA file extension | Synium Software | CleanApp Archive Format |
| CAB file extension | Microsoft | Windows Cabinet Compressed Archive |
| CABAL file extension | N/A | Haskell Cabal |
| CAC file extension | dataBased Intelligence, Inc. | DBASE IV Executable |
| CACHE file extension | N/A | Generally Cache Format |
| CACHE-2 file extension | VideoLAN Project Team | VLC Media Player Font Cache |
| CACHE-3 file extension | N/A | VLC Media Player Font Cache |
| CACHE2 file extension | Parametric Technology Corporation | Pro/Engineer |
| CACTION file extension | Apple | Apple Mac OS X Automator Conversion Action Format |
| CAD file extension | BobCAD-CAM | CAD Drawing Format |
| CADC file extension | Corpatla | Corpatla Baudadministration Data Format |
| CADRG file extension | N/A | Compressed ARC Raster Graphic |
| CAE file extension | Dassault Systèmes S.A. | Abaqus CAE Model |
| CAF file extension | Apple | Apple Core Audio Format |
| CAFF file extension | Apple | Apple Core Audio Format |
| CAG file extension | Microsoft | Microsoft Clip Gallery Catalog Format |
| CAH file extension | Corel Corporation | Ulead Photo Explorer Thumbnail Cache |
| CAI file extension | Naviter d.o.o. | SeeYou Flight Data |
| CAJ file extension | N/A | China Academic Journals Full-text Database |
| CAKEWALKWINDOWLAYOUT file extension | N/A | Cakewalk Window Layout |
| CAL file extension | Broderbund | Calendar Format |
| CALB file extension | Coolect | Coolect Album Format |
| CALIBRE file extension | Calibre | Calibre Device Data Format |
| CALIBZ file extension | Chief Architect, Inc. | Chief Architect Symbol |
| CALS file extension | N/A | CALS Raster Group 1 Image Format |
| CALX file extension | Microsoft Corporation | Calendar Printing Assistant Template |
| CAM file extension | N/A | Gerber CAM Job Format |
| CAMM file extension | Corpatla | Espresso Mind Map Mind Map Format |
| CAMP file extension | Microsoft | WCS CAMP |
| CAMPROJ file extension | TechSmith | Camtasia Studio Project Format |
| CAMREC file extension | TechSmith | Camtasia Studio Recorder Format |
| CAMTHTR file extension | TechSmith Corporation | Camtasia Studio Theater |
| CAMV file extension | TechSmith | Camtasia Screencast Video Format |
| CAN file extension | Canon | Canon Navigator Fax Format |
| CANF file extension | Abbot Systems | CanOpener |
| CANIM file extension | Klei Entertainment Inc. | Shank Game |
| CANNEDSEARCH file extension | Apple, Inc. | Apple Mac OS X Finder Predefined Search |
| CAOS file extension | Abbot Systems | CanOpener Preference |
| CAP file extension | Scirra | Construct Game Development Format |
| CAPFILE file extension | Ruby community | Ruby Capistrano Instruction |
| CAPROJ file extension | Scirra | Construct Game Project Format |
| CAPS file extension | GoldGingko Software | CaptureSaver |
| CAPX file extension | Scirra | Construct Game Project Archive Format |
| CAR file extension | QUALCOMM | Brew MP Component Application Resource Format |
| CARB file extension | Apple, Inc. | Apple Mac OS X Carbon Package |
| CARC file extension | Nintendo | Nintendo DS Compressed Archive Format |
| CARD file extension | RealArcade.com | Funkiball Adventure |
| CARO file extension | N/A | Adobe Acrobat Creatorcode |
| CAS file extension | Autodesk | Autodesk AutoCAD License Format |
| CASCII file extension | N/A | CACTVS Chemical ASCII Format |
| CASE file extension | Bohemian Coding | SlipCover For Mac Template Format |
| CAT file extension | N/A | Advanced Disk Catalog Database Format |
| CAT4D file extension | MAXON Computer GmbH | Cinema 4D Catalog |
| CATALOG file extension | Dassault Systèmes S.A. | CATIA Catalog |
| CATANALYSIS file extension | Dassault Systèmes S.A. | CATIA Analysis |
| CATDRAWING file extension | Dassault Systèmes S.A. | CATIA Drawing |
| CATFCT file extension | Dassault Systèmes S.A. | CATIA CATfct |
| CATKNOWLEDGE file extension | Dassault Systèmes S.A. | CATIA CATKnowledge |
| CATMATERIAL file extension | Dassault Systèmes S.A. | CATIA CATMaterial |
| CATOM file extension | Chief Architect, Inc. | Chief Architect Catalogue |
| CATPART file extension | Dassault Systemes | CATIA Part Format |
| CATPREFERENCES file extension | Dassault Systèmes S.A. | CATIA Preferences |
| CATPROCESS file extension | Dassault Systèmes S.A. | CATIA Process |
| CATPRODUCT file extension | Dassault Systemes | CATIA Product Format |
| CATRASTER file extension | Dassault Systèmes S.A. | CATIA Raster |
| CATRESOURCE file extension | Dassault Systèmes S.A. | CATIA Resource |
| CATSETTINGS file extension | Dassault Systèmes S.A. | CATIA Settings |
| CATSHAPE file extension | Dassault Systèmes S.A. | CATIA Shape |
| CATSWL file extension | Dassault Systèmes S.A. | CATIA CATSwl |
| CATSYSTEM file extension | Dassault Systèmes S.A. | CATIA Functional Systems |
| CAV file extension | Comodo Group | Comodo Virus Definitions Format |
| CAWR file extension | Corpatla | Espresso Workreport Format |
| CAX file extension | Visual Collaboration Technologies Inc. | VCollab 3D Model |
| CB file extension | Microsoft Corporation | Microsoft Clean Boot |
| CB1 file extension | SINTEF | CARE-S InfoWorks Biochemical Oxygen Detail |
| CB4 file extension | Actuate Corporation | Actuate Analytics |
| CB7 file extension | N/A | CDisplay 7-Zip Comic Book Format |
| CBA file extension | N/A | CDisplay ACE Comic Book Format |
| CBB file extension | ChessBase GmbH | ChessBase Search Booster |
| CBC file extension | Calibre | Comic Book Collection |
| CBCP file extension | CodeBaby Corp. | CodeBaby Production Studio Character Package |
| CBD file extension | Corel Corporation | Corel WordPerfect Dictionary |
| CBDS file extension | Nicom00k | Comic Book DS Format |
| CBF file extension | Tailwag Software | Calendar Builder Saved Calendar Format |
| CBG file extension | N/A | CyberGauge Data Format |
| CBH file extension | ChessBase | ChessBase Chess Database Format |
| CBK file extension | N/A | Backup Configuration Format |
| CBL file extension | N/A | Cobol Language Source Code Format |
| CBM file extension | N/A | Bitmap Image Format |
| CBMV file extension | Beaver Valley Software | Comic Book Millennium Collection |
| CBN file extension | j2 Global Communications, Inc. | PaperMaster Cabinet |
| CBO file extension | Microsoft Corporation | Microsoft Interactive Training |
| CBP file extension | Code::Blocks | Code::Blocks Project Format |
| CBPLUGIN file extension | The Code::Blocks Team | Code::Blocks Plugin |
| CBPROJ file extension | Embarcadero Technologies, Inc. | C++ Builder Project |
| CBQ file extension | Valemount Networks Corporation | StarOS Script |
| CBR file extension | N/A | Comic Book Archive Format Or ComicBook Reader Format |
| CBS file extension | Pelican Accessories | Code Breaker PS2 Save Format |
| CBT file extension | Microsoft | Computer Based Training |
| CBU file extension | Comodo Group | Comodo Backup Backup Format |
| CBV file extension | ChessBase | ChessBase Archive Format |
| CBW file extension | ComicRacks Team | ComicRack Webcomics |
| CBX file extension | IBM | Rational XDE |
| CBXML file extension | Shpakovski | CodeBox XML Library |
| CBZ file extension | N/A | Comic Book Archive Format Or ComicBook Reader Format |
| CC file extension | N/A | C++ Language Source Code Format |
| CC1 file extension | Briggs Softworks | Briggs Softworks Calendar Commander |
| CCA file extension | Clickteam | Multimedia Fusion Format |
| CCB file extension | Microsoft Corporation | Visual Basic Animated Button Configuration |
| CCBJS file extension | Ambiera | CopperCube JavaScript Scene |
| CCC file extension | Microsoft Corporation | Microsoft Internet Chat Conversation Log |
| CCD file extension | N/A | CloneCD Track Description Format |
| CCE file extension | N/A | Calendar Creator 2 Event |
| CCF file extension | CryptLoad | CryptLoad Container Format |
| CCGAME file extension | Microsoft | Microsoft XNA Game Studio Game Package Format |
| CCH file extension | Corel | CorelDRAW Corel Chart Format |
| CCIP file extension | Curse | Curse Client 4 Addon Download Protocol Format |
| CCJ file extension | WordWeb Software | Crossword Compiler Compiled Crossword Applet |
| CCK file extension | N/A | Corel Clipart |
| CCL file extension | Translucent Dragon | CCTools Levelset |
| CCM file extension | ClickTeam | Multimedia Fusion Custom Menu |
| CCN file extension | Clickteam | Multimedia Fusion Development Format |
| CCO file extension | Apple, Inc. | Apple Cocoa |
| CCP file extension | RIB Software | RIB Import Converter Profile |
| CCR file extension | N/A | HealthFrame ASTM Continuity Of Care Record Format |
| CCRF file extension | N/A | Calcomp Raster Bitmap Image |
| CCS file extension | YesSoftware | CodeCharge Studio Project Format |
| CCSCC file extension | IBM | ClearCase Source Control Info Format |
| CCT file extension | Adobe Systems | Macromedia (Adobe) Director Shockwave Cast Format |
| CCW file extension | WordWeb Software | Crossword Compiler Saved Puzzle |
| CCWSLN file extension | Rockwell Automation, Inc. | Connected Components Workbench |
| CCX file extension | N/A | Click & Create Extension |
| CCXML file extension | N/A | Call Control EXtensible Markup Language |
| CD file extension | Microsoft | ClassDiagram Format |
| CD2 file extension | Avery | ClickN Design 3D CD Label Format |
| CD5 file extension | John Paul Chacha's Lab | Chasys Draw Image |
| CDA file extension | N/A | CD Audio Track |
| CDATA file extension | Electronic Arts, Inc. | Command & Conquer 3 Audio |
| CDB file extension | Nokia | Symbian OS Contact Database Format |
| CDC file extension | Autodesk | Autodesk AutoCAD DesignCenter Preview Cache Format |
| CDD file extension | Computer Systems Odessa | ConceptDraw Drawing Diagram Format |
| CDDA file extension | N/A | Apple ITunes AIFF Audio Format |
| CDDX file extension | Circuit Diagram | Circuit Diagram Diagram Format |
| CDE file extension | Kubotek USA Inc. | CADKEY Dynamic Extension |
| CDEM file extension | CompeGPS TEAM S.L. | CompeGPS Land Landscape |
| CDF file extension | ECMG | Content Definition Format |
| CDF-MS file extension | Microsoft | ClickOnce Deployment Binary Manifest Format |
| CDFX file extension | Indexing Research | Cindex |
| CDG file extension | N/A | Compact Disc Plus Picture Image Format |
| CDI file extension | Padus | DiscJuggler Image Format |
| CDJ file extension | Padus, Inc. | DiscJuggler CD-ROM Data |
| CDK file extension | N/A | Calamus SL Document |
| CDL file extension | Kubotek | CADKey CAD Language Format |
| CDLX file extension | Adobe Systems | Adobe Audition Audio CD Project Format |
| CDM file extension | NTI | NTI CD&DVD-Maker Image Format |
| CDMEDIA file extension | N/A | Boxer For Mac Cd-rom |
| CDMM file extension | Computer Systems Odessa | ConceptDraw MINDMAP Document |
| CDMP file extension | Microsoft | WCS CDMP |
| CDMT file extension | Computer Systems Odessa | ConceptDraw MINDMAP Template |
| CDMTZ file extension | Computer Systems Odessa | Compressed ConceptDraw MINDMAP Template |
| CDMZ file extension | Computer Systems Odessa | ConceptDraw MINDMAP Compressed Document Format |
| CDO file extension | NCH Software | Crescendo Music Score Format |
| CDOC file extension | SK.ee | DigiDoc Client Container |
| CDP file extension | N3V Games | Trainz Simulator Content Dispatcher Pack Format |
| CDP2 file extension | N3V Games | Trainz Classics Content Dispatcher Pack 2 Format |
| CDPX file extension | CS Odessa | ConceptDraw PROJECT XML Format |
| CDPZ file extension | CS Odessa | ConceptDraw PROJECT Document |
| CDR file extension | Corel | CorelDRAW Vector Or Bitmap Format |
| CDR3 file extension | Corel Corporation | CorelDRAW 3 For Mac Vector Or Bitmap Image |
| CDR4 file extension | N/A | CorelDRAW 4 For Mac Vector Or Bitmap Image |
| CDR5 file extension | N/A | CorelDRAW 5 For Mac Vector Or Bitmap Image |
| CDR6 file extension | Corel Corporation | CorelDRAW 6 For Mac Vector Or Bitmap Image |
| CDRW file extension | Corel Corporation | CorelDRAW For Mac |
| CDRX file extension | Robert Bosch GmbH | Bosch Crash Data Retrieval Data Format |
| CDRZIP file extension | N/A | DICOM Compressed Image |
| CDS file extension | CambridgeSoft Corporation | ChemDraw Stationery Document |
| CDSG file extension | Conrad Albrecht | DrawMusic Chord Song |
| CDT file extension | Corel | CorelDRAW Template Format |
| CDT6 file extension | N/A | CorelDRAW 6 For Mac Template |
| CDT_ file extension | N/A | CorelDRAW For Mac Template |
| CDU file extension | N/A | CDU Paint Image Format |
| CDV file extension | Square Box Systems Ltd. | CatDV Catalog |
| CDW file extension | ASCON | KOMPAS CAD Drawing Format |
| CDX file extension | N/A | Compound Index Format |
| CDXML file extension | CambridgeSoft | ChemDraw XML Format |
| CDZ file extension | N/A | Compressed CD Image Format |
| CE file extension | Digital Vision | Digital Vision ComputerEyes IFF Bitmap Format |
| CE0 file extension | N/A | Winewar Worm |
| CE1 file extension | N/A | Computer Eyes Raw Image Format |
| CE2 file extension | N/A | Computer Eyes Raw Image Format |
| CEA file extension | DAZ 3D Inc. | DAZ 3D Carrara Pro Export |
| CEB file extension | Apabi | Apabi EBook Format |
| CED file extension | N/A | JVC Corrupted Video Format |
| CEDATA file extension | Cloud Engines, Inc. | Pogoplug |
| CEDPRJ file extension | Ashampoo | Ashampoo CoverEditor Cover Project Format |
| CEF file extension | CenturionSoft | CenturionMail Format |
| CEI file extension | School of Aquatic & Fishery Sciences, University of Washington | CRiSP Harvest |
| CEIMG file extension | mdSOFT | CeRegEditor Registry Image |
| CEL file extension | N/A | Adobe Audition Loop Format |
| CELL file extension | Castep team | CASTEP Supercell Material Data |
| CELTX file extension | Celtx | Celtx Project Format |
| CELX file extension | Celestia Development Team | Celestia Script |
| CEM file extension | Tilted Mill Entertainment | Children Of The Nile Model Format |
| CEO file extension | N/A | Winewar Worm |
| CER file extension | N/A | Internet Security Certificate |
| CERT file extension | AOL Inc. | Netscape Certificate Index |
| CERTAUTHORITYCONFIG file extension | Apple, Inc. | Apple Mac OS X Certificate Assistant Configuration |
| CERTSIGNINGREQUEST file extension | Apple, Inc. | Apple Mac OS X Certificate Assistant |
| CET file extension | N/A | Hitachi Cobol |
| CETRAINER file extension | N/A | DBVM |
| CEX file extension | Dassault Systemes | SolidWorks Enterprise PDM Vault Export Format |
| CF file extension | N/A | Sendmail Configuration Format |
| CF2 file extension | N/A | Common File Format 2 |
| CF5 file extension | DocuWare AG | DocuWare |
| CF7 file extension | Toshiba Corporation | Toshiba ConfigFree Profile Handling Module |
| CFA file extension | Adobe Systems | Adobe Premiere Pro Audio Format |
| CFB file extension | Cleverfiles | Disk Drill Recovered |
| CFC file extension | Adobe Systems | Adobe ColdFusion Component Format |
| CFD file extension | Ranquel Technologies | CryptoForge Document |
| CFDI file extension | N/A | Comprobante Fiscal Digital Por Internet |
| CFE file extension | Ranquel Technologies | CryptoForge Encrypted |
| CFF file extension | N/A | Common File Format |
| CFF2 file extension | Eastman Kodak Company | Kodak Pandora Exported |
| CFG file extension | N/A | Configuration Files |
| CFGE file extension | iWin | Jewel Quest Configuration Format |
| CFI file extension | CleverForm Ltd. | CleverForm Script |
| CFK file extension | N/A | Microsoft Developer Studio Diagram |
| CFL file extension | IMVU | IMVU Product Format |
| CFM file extension | Adobe Systems | Adobe ColdFusion Template Format |
| CFML file extension | Adobe Systems | Adobe ColdFusion Markup Language Format |
| CFN file extension | invers Software | Calamus Font Data |
| CFO file extension | Embarcadero Technologies, Inc. | Turbo C Utilities C Form Object |
| CFP file extension | Answers 2000 Limited | Bitmap Native Format For CoverFactory |
| CFPRESET file extension | N/A | SA Color Finesse Plugin For Adobe After Effects |
| CFR file extension | Z8Games | Cross Fire Replay Format |
| CFREPLAY file extension | SmileGate | Crossfire Europe Replay |
| CFS file extension | Pismo Technic | Compact File Set File Format |
| CFT file extension | N/A | CFast Graphics |
| CFW file extension | PerkinElmer Inc. | ChemFinder Form |
| CFX file extension | MAGIX AG | Magix Movie Edit Pro |
| CFXR file extension | cfxr | Cocoa Sfxr Format |
| CFXXE file extension | N/A | Possibly Malware |
| CFZ file extension | N/A | Compressed Archive |
| CG file extension | NVIDIA | NVidia CgFX Format |
| CG3 file extension | CABRILOG | Cabri 3D Document |
| CG4 file extension | N/A | CALS Group IV Bitmap Graphics |
| CGA file extension | Crytek | CryENGINE Vehicle Animation Format |
| CGD file extension | N/A | CricketGraph Data |
| CGDB file extension | Microsoft Corporation | Microsoft Clip Art Package |
| CGF file extension | Ubisoft | Far Cry 3D Model Format |
| CGFX file extension | NVIDIA | CgFX Shader Format |
| CGI file extension | N/A | Common Gateway Interface Script Format |
| CGINC file extension | Unity Technologies | Unity Custom Shader Include |
| CGK file extension | IVT Corporation | BlueSoleil |
| CGM file extension | N/A | Computer Graphics Metafile |
| CGMAP file extension | Probki.net | CityGuide Region Map |
| CGO file extension | PopTop Software Inc. | Railroad Tycoon 3 Car Properties |
| CGP file extension | CodeGazer | PixelCryptor Encrypted Format |
| CGR file extension | Act-3D | Quest3D Visualisation Scene Format |
| CGRP file extension | Avid Technology | Pro Tools Clip Group Format |
| CGT file extension | Gold Parsing System Team | Gold Parsing System Compiled Grammar Table |
| CGVP file extension | NVIDIA Corporation | NVidia Cg Programming Language XML |
| CGX file extension | ARM Holdings plc | ARM RL-TCPnet HTTP Web Server XML Web Page Update Script |
| CGZ file extension | N/A | Linux Drivers Archive Format |
| CH file extension | IBM | OS/2 Configuration |
| CH1 file extension | IBM | IBM Freelance Graphics Chart |
| CH10 file extension | Bob Baggerman | Irig 106 Original Recording |
| CH3 file extension | Harvard Graphics | Harvard Graphics V3.0 Chart/image Format |
| CH4 file extension | Nanotec | WSxM |
| CH5 file extension | Department of Energy (DOE) Advanced Simulation and Computing Initiative (ASCI) | VisIt |
| CHA file extension | N/A | Online Chat Configuration Format |
| CHAM file extension | Zaplots | Compiled HAM Format |
| CHAP file extension | N/A | MP4 Movie Chapter |
| CHARMM file extension | The CHARMM Development Project | CHARMm Chemical Modeller Input |
| CHARSET file extension | N/A | Character Set Format |
| CHART file extension | TurkeyMan | Feedback Chart Format |
| CHAT file extension | N/A | Online Chat Configuration Format |
| CHATLOG file extension | N/A | Adium Chat Log |
| CHC file extension | HCFR Mag | HCFR Colorimeter Data Format |
| CHD file extension | The MAME Team | MAME Compressed Hard Disk Format |
| CHE file extension | Procedimientos-Uno, S.L. | CHwinEHE Project |
| CHEF file extension | David Morgan-Mar | Chef Source Code Format |
| CHESSTITANSSAVE-MS file extension | Microsoft | Chess Titans Save Game Format |
| CHF file extension | Symantec Corporation | PcAnywhere Remote Control |
| CHG file extension | N/A | Quicken Online Data Format |
| CHH file extension | N/A | C++ Header |
| CHI file extension | Microsoft Corporation | Microsoft Help Index |
| CHJ file extension | IBM | IBM SPSS Interview Cache |
| CHK file extension | N/A | ScanDisk File Fragment |
| CHKN file extension | IMVU, Inc. | IMVU Create Mode Temporary |
| CHKSPLIT file extension | Incredible Bee | Incredible Bee Archiver Checksum |
| CHL file extension | Leadtek Research | Leadtek WinFast PVR2 Channel List Format |
| CHM file extension | Microsoft | Microsoft Compiled HTML Help Format |
| CHML file extension | Krasbit Technologies | Chameleon Encrypted Format |
| CHN file extension | N/A | Ethnograph Data Format |
| CHO file extension | Hash, Inc. | Animation:Master Choreography |
| CHP file extension | Corel Corporation | Ventura Publisher Chapter Document |
| CHQ file extension | Microsoft Corporation | Microsoft Help Combined Full-text Search |
| CHR file extension | Autodesk | Autodesk 3D Studio Max Character Format |
| CHRPARAMS file extension | Crytek | CryENGINE Character Paramters Format |
| CHS file extension | Microsoft | Windows Chinese Noise-Word List Format |
| CHT file extension | N/A | ZSNES Cheat Code Format |
| CHTML file extension | N/A | Compact HTML Document |
| CHUNK001 file extension | Filesplitter.org | File Splitter Split File (part 1) |
| CHV file extension | ChGroup | ChView Star Map Format |
| CHW file extension | Microsoft | Microsoft Help HTML Help General Index Format |
| CHX file extension | Autodesk | Autodesk AutoCAD Standards Check Format |
| CI file extension | Microsoft | Windows Content Indexer Catalog Format |
| CID file extension | Institut Straumann | CoDiagnostiX User Defined Implant |
| CIDB file extension | Apple | Apple ITunes CD Information Format |
| CIF file extension | Corel | Easy CD Creator CD Image Format |
| CII file extension | Intergraph Corporation | Caesar II |
| CIK file extension | N/A | Corel Graphics 10 Custom Dual Tone |
| CIL file extension | Microsoft | Microsoft Office Clip Gallery Download Package |
| CIM file extension | CIMEX Corporation | CimPack Design Drawing |
| CIMG file extension | CImg | CImg Image Format |
| CIN file extension | Kodak | Kodak Cineon Image Format |
| CIN96LM file extension | Microsoft Corporation | Microsoft Cinemania |
| CIN96UPD file extension | Microsoft Corporation | Microsoft Cinemania Format |
| CINE file extension | Vision Research | Vision Research Phantom Cine Camera Video Format |
| CINEMA4D file extension | MAXON Computer GmbH | Cinema 4D For Amiga |
| CIO file extension | Grassland, Soil & Water Research Laboratory | SWAT Master Watershed |
| CIP file extension | Cavena | Cavena Subtitles Format |
| CIPO file extension | Cartesian Products, Inc. | Cartesian Products Compressed Internet Document |
| CIR file extension | N/A | Supermax ECAD Command Save |
| CIRC file extension | Logisim Team | Logisim Circuit |
| CIRCUIT file extension | KTechlab | KTechlab Circuit Design Format |
| CIS file extension | VicTech Software | CheckInbox |
| CISO file extension | N/A | Wii Compressed Game Image |
| CIT file extension | Intergraph | Intergraph Scanned Image |
| CIV file extension | Activision Blizzard, Inc. | Empire Earth Custom Civilization Information |
| CIV5MAP file extension | Firaxis Games | Civilization 5 Map |
| CIV5SAVE file extension | Take-Two Interactive Software | Civilization 5 Saved Game Format |
| CIW file extension | N/A | Web Of Science Export |
| CIX file extension | IBM | Rational XDE |
| CJSTYLES file extension | Codejock Software | Skin Builder Project |
| CK1 file extension | id Software LLC | Commander Keen 1 Game Data |
| CK2 file extension | id Software LLC | Commander Keen 2 Game Data |
| CK3 file extension | id Software LLC | Commander Keen 3 Game Data |
| CK4 file extension | id Software LLC | Commander Keen 4 Game Data |
| CK5 file extension | id Software LLC | Commander Keen 5 Game Data |
| CK6 file extension | id Software LLC | Commander Keen 6 Game Data |
| CK9 file extension | DVO Enterprises | DVN Cookn Cookbook Backup Format |
| CKA file extension | Comfort Software Group | Comfort Keys Database |
| CKB file extension | Cricket Technology | Cricket Audio Sound Bank Format |
| CKBX file extension | Cricket Technology | Cricket Audio XML Bank Description Format |
| CKD file extension | Kubotek | Kubotek Design Container |
| CKF file extension | Casio | Casio Keyboard Audio Format |
| CKP file extension | Microsoft | Microsoft SQL Server Checkpoint Format |
| CKS file extension | N/A | Microsoft Windows CE Image Info |
| CKT file extension | Altium | B2 Spice Circuit Design Format |
| CKZ file extension | N/A | QuickSFV File Verification Database |
| CL file extension | Aha-Soft | IconUtils Mouse Cursor Library Format |
| CL2 file extension | HY-TEK Sports Software | HY-TEK Meet Results Format |
| CL2ARC file extension | Plasq | Comic Life 2 Document Archive Format |
| CL2DOC file extension | Plasq | Comic Life 2 Document Format |
| CL2LYT file extension | Plasq | Comic Life 2 Layout Format |
| CL2TPL file extension | Plasq | Comic Life 2 Template Format |
| CL3 file extension | N/A | Easy CD Creator CD Layout |
| CL4 file extension | Sonic Solutions | Easy CD Creator CD Layout Format |
| CL5 file extension | Roxio | Easy CD Creator Saved Project Format |
| CLA file extension | SoftVelocity | Clarion For DOS Source Code |
| CLAF file extension | Apple, Inc. | Claris Font |
| CLAM file extension | Adobe Systems Incorporated | Adobe InDesign Dictionary |
| CLARIFY file extension | Blue Mango Learning Systems | Blue Mango Clarify Document Format |
| CLAS file extension | Oracle Corporation | Java Class |
| CLASS file extension | Oracle | Java Bytecode Class Format |
| CLASSDIAGRAM file extension | Microsoft Corporation | Microsoft Visual Studio Class Diagram |
| CLASSLIST file extension | SMART Technologies | SMART Notebook Class List Format |
| CLASSPATH file extension | The Eclipse Foundation | Eclipse IDE JAVA Project Related |
| CLB file extension | Microsoft | Com+ Catalog Format |
| CLBX file extension | Brian Pipa and PipaSoft | MP3 Automagic CD Cover Creator Label |
| CLC file extension | N/A | Microsoft Schedule+ 7 Habits Mission Statement |
| CLD file extension | Canon | Canon CD-Label Print Label Layout Format |
| CLDCVT file extension | N/A | CD-LabelPrint Converted Data |
| CLDLYR file extension | Planetside Software | TerraGen Cloud Layer |
| CLE file extension | Moon Valley Software, Inc. | Icon Lock-iT Locked File Indicator |
| CLEO file extension | CLEO | Grand Theft Auto Vice City Mod Format |
| CLF file extension | Ilium Software, Inc. | ListPro |
| CLG file extension | Microsoft | Microsoft Windows System Image Manager Catalogue Format |
| CLGX file extension | Galleria Software | Collage Maker Collage |
| CLI file extension | HawkSoft | Client Management System Customer |
| CLIPPING file extension | Apple, Inc. | Apple Mac OS X Finder |
| CLIPS file extension | Panic | Coda For Mac Clips Format |
| CLIX file extension | Rixstep | CLIX Command Format |
| CLJ file extension | N/A | Clojure Source Code |
| CLK file extension | Corel | CorelDRAW Corel R.A.V.E. Animation Format |
| CLKK file extension | N/A | Clicker Keyboard Format |
| CLKT file extension | N/A | Clicker Template Format |
| CLKW file extension | N/A | Clicker Word Bank Format |
| CLKX file extension | N/A | Clicker Grid Set Format |
| CLL file extension | Crick Software Ltd. | Crick Software Clicker |
| CLM file extension | YMAX | Micrografx Picture Publisher Macro Format |
| CLN file extension | Microsoft Corporation | Microsoft Windows 3.x Configuration Backup |
| CLO file extension | N/A | Cloe Ray-Tracer Image |
| CLOE file extension | N/A | Cloe Ray-Tracer Image |
| CLOUD file extension | N/A | GOM Atos Scanner |
| CLP file extension | N/A | Microsoft Windows Clipboard Format |
| CLPI file extension | Blu-ray Disc Association | Blu-Ray Clip AV Stream Format |
| CLPPRJ file extension | CodeLobster Software | CodeLobster PHP Edition Project |
| CLR file extension | Adobe Systems | Adobe Flash Color Table Format |
| CLR0 file extension | N/A | Nintendo Wii Color Swapping Animation |
| CLS file extension | N/A | LaTeX Format |
| CLT file extension | Clarity Legal | Clarity Legal Transcript Format |
| CLU file extension | Revolution Software | Broken Sword 2 Dialogue |
| CLV file extension | Ilgam Zulkorneev | QIP Visible List |
| CLW file extension | Microsoft | Microsoft Visual C++ MFC Class Wizard Information Format |
| CLX file extension | Adobe Systems | Adobe Standard Dictionary Format |
| CLY file extension | Corel Corporation | CorelDRAW Custom Layout |
| CLZ file extension | Core Design | Tomb Raider: The Angel Of Darkness Game |
| CM file extension | Rockstar Games | Grand Theft Auto CLEO Custom Mission Format |
| CM10 file extension | LexisNexis | CaseMap Case Format |
| CM2 file extension | Smith Micro | Poser Camera Set Format |
| CM3 file extension | LexisNexis | CaseMap Data |
| CM4 file extension | Thornsoft Development, Inc. | ClipMate Data |
| CM5 file extension | N/A | LexisNexis Case Analysis |
| CM8 file extension | LexisNexis | CaseMap Case |
| CMA file extension | IBM | Applix TM1 Database Format |
| CMAKE file extension | Kitware, Inc. | CMake Module |
| CMAP file extension | IHMC | CmapTools Concept Map Format |
| CMB file extension | Dionex Corporation | Chromeleon Backup Archive |
| CMBL file extension | Vernier Software & Technology | Logger Pro Data Format |
| CMC file extension | Bitz & Pixelz BV | Comic Collector Collection Data |
| CMD file extension | N/A | Microsoft Windows Command Script Format |
| CMDB file extension | ANSYS Inc. | ANSYS CFX Mesh Database |
| CMDF file extension | CrystalMaker Software Ltd. | CrystalMaker Data |
| CMDT file extension | Apple, Inc. | Claris Dictionary |
| CME file extension | Viva Media | Crazy Machines Level Format |
| CMF file extension | Creative Labs | Creative Labs FM-synthesis Music Format |
| CMG file extension | Ubisoft Entertainment S.A. | ChessMaster Saved Game |
| CMI file extension | LucasArts Entertainment Company, LLC | The Dig Bundle |
| CML file extension | N/A | Chemical Markup Language Document Format |
| CMM file extension | Corel | Corel Multimedia Manager Album Format |
| CMMCD file extension | TechSmith Corporation | Camtasia Studio MenuMaker Project |
| CMMP file extension | TechSmith | Camtasia MenuMaker Project |
| CMMTHEME file extension | MacPaw | CleanMyMac Theme Format |
| CMMTPL file extension | TechSmith | Camtasia MenuMaker Template |
| CMN file extension | Microsoft Corporation | Systems Management Server (SMS) Update |
| CMO file extension | Blanchard | Spanish Whiz Sound |
| CMOD file extension | Celestia Development Team | Celestia Model Format |
| CMP file extension | Siemens | Solid Edge Wire Harness Format |
| CMPROJ file extension | TechSmith | Camtasia For Mac Project Format |
| CMP_XML file extension | Siemens Product Lifecycle Management Software Inc. | Solid Edge XML Design |
| CMR file extension | Foundation CMA | Coach Saved Results |
| CMRBK file extension | LexisNexis | CaseMap ReportBook Definition |
| CMREC file extension | TechSmith | Camtasia For Mac Record Format |
| CMS file extension | N/A | Content Management System Web Page Format |
| CMT file extension | N/A | Chinon ES-1000 Digital Camera Image Format |
| CMTX file extension | Rick Meyers | E-Sword Commentary |
| CMU file extension | N/A | CMU Window Manager Bitmap Image |
| CMV file extension | Corel Corporation | CorelDRAW CorelMove Animation |
| CMW file extension | Microsoft Corporation | Microsoft Office Custom Maintenance Wizard Data |
| CMX file extension | Corel | Corel Presentation Exchange Format |
| CMY file extension | Corel Corporation | CorelDRAW Custom |
| CMZ file extension | Smith Micro | Poser Compressed Camera Set Format |
| CN file extension | Procedimientos-Uno, S.L. | CNwin/MLwin Account |
| CN1 file extension | MITRE | CNR Modem Initialization Data Format |
| CN3 file extension | National Center for Biotechnology Information | CN3D |
| CNA file extension | OpEx Software | Catena Project Format |
| CNB file extension | David Harris | Pegasus Mail Noticeboard Mail Stored Message |
| CNC file extension | N/A | CNC Machine Tool Path Format |
| CNC3CAMPAIGN file extension | Electronic Arts, Inc. | Command And Conquer 3 Campaign Save Game |
| CND file extension | Melco | Melco Condensed Embroidery Format |
| CNDX file extension | Avery | Avery DesignPro For Mac Label Format |
| CNF file extension | N/A | Network Configuration Format |
| CNG file extension | Vassil Arabadjiev | CryptoNG Encrypted Format |
| CNI file extension | Center for Comparative NeuroImaging | CWBench |
| CNK file extension | Microsoft Corporation | Microsoft Dynamics GP Chunk |
| CNM file extension | LexisNexis | NoteMap Outline Format |
| CNN file extension | N/A | ADO-network Connection Configuration |
| CNO file extension | Teldas GmbH | INet-Server Error Description |
| CNQ file extension | Bloomerang Software, Inc. | WebShop Platinum Project |
| CNR file extension | David Harris | Pegasus Mail Mail Message Stored In Systemwide Folder |
| CNS file extension | Elecbyte | M.U.G.E.N. Character States Format |
| CNT file extension | Microsoft | Help Contents Format |
| CNTK file extension | Microsoft Corporation | Microsoft Outlook Express Contact |
| CNTL file extension | Desktop Aeronautics | GoCart Control |
| CNV file extension | ACD Systems | Canvas Drawing Format |
| CNX file extension | David Harris | Pegasus Mail |
| CO file extension | Vellum Investment Partners, LLC | Cobalt 3D |
| COA file extension | Caligari Corporation | Caligari TrueSpace 3D Object |
| COB file extension | N/A | COBOL Programming Language Source Format |
| COC file extension | Olle Persson | Bibexcel |
| COD file extension | N/A | Blackberry Compiled Java Code |
| CODAPLUGIN file extension | Panic | Coda For Mac Plugin Format |
| CODASITE file extension | Panic | Coda For Mac Web Project Format |
| COE file extension | N/A | Xilinx BRAM Initialization |
| COF file extension | Microchip Technology | MPLAB COFF Format |
| COFFEE file extension | N/A | CoffeeScript Script Format |
| COK file extension | Teldas GmbH | INet-Server Error Report |
| COL file extension | Rockstar Games | Grand Theft Auto III Collision Data Format |
| COLLECTION file extension | Adobe Systems | Adobe Bridge Collection Format |
| COLLISIONMESH file extension | Electronic Arts, Inc. | Battlefield Collision Mesh |
| COLLOQUYTRANSCRIPT file extension | Javelin.cc | Colloquy Chat Transcript |
| COLOR file extension | W3C | Amaya Config |
| COLORPICKER file extension | Apple | Apple Mac OS X Color Picker Component |
| COLORS file extension | Richard Hughey - Kevin Karplus - Anders Krogh | SAM Makelogo Color |
| COLOURSCHEME file extension | J&ASoft | J&ASoft Speedy Browser Color Scheme Settings |
| COLR file extension | Greg Landweber and Arlo Rose | Kaleidoscope Scheme |
| COLZ file extension | Adobe Systems | Adobe Collage Moodboard Format |
| COM file extension | N/A | Command Executable Format |
| COMFYCAKESSAVE-MS file extension | Microsoft | Comfy Cakes Saved Game Format |
| COMICDOC file extension | Plasq | Comic Life Document Format |
| COMMAND file extension | Apple | Apple Mac OS X Terminal Format |
| COMMANDERDOC file extension | Apple, Inc. | Apple Qmaster |
| COMMON file extension | Apple, Inc. | Unix Script |
| COMP file extension | Freescale Semiconductor, Inc. | CodeWarrior Compiler |
| COMPARISON file extension | Araxis Ltd. | Merge Comparison Report |
| COMPLETE file extension | KJB Software development | SendSafe Deciphered E-message |
| COMPO file extension | N/A | DAZ 3D Carrara Pro 7 Or 8 Temporary |
| COMPONENT file extension | N/A | Mac OS X System Component |
| COMPONENTDIAGRAM file extension | Microsoft Corporation | Microsoft Visual Studio Component Diagram |
| COMPONENTS file extension | Apple, Inc. | Mac OS X System |
| COMPOSITEFONT file extension | Microsoft | Composite Font Format |
| COMPOSITIONMODEL file extension | Invantive BV | Invantive Composition Data Model |
| COMPRESS file extension | N/A | Microsoft Compress |
| COMPRESSED file extension | WordCompress | WordCompress Compacted Web Format |
| CON file extension | RadGs | Concept Application Server Source Code Format |
| CONF file extension | N/A | Configuration Information Format |
| CONFIG file extension | N/A | Configuration Format |
| CONFIGPROFILE file extension | Apple | Apple Configuration Profile |
| CONFIGURE file extension | The Open Group | Bash |
| CONFLUENCE file extension | The Eclipse Foundation | Eclipse Mylyn WikiText Confluence |
| CONFORM file extension | Maggot Software | Conformalizer Change List Format |
| CONSOLE file extension | Microsoft Corporation | Widows NT Console |
| CONT file extension | Panasonic Corporation | Panasonic Camcorder Extra |
| CONTACT file extension | Microsoft | Microsoft Windows Contact Format |
| CONTENTPROJ file extension | Microsoft Corporation | XNA Game Studio Game Content Project |
| CONTENTS file extension | Apple, Inc. | MAC OS X |
| CONTENTSOFCLIPBOARD file extension | Microsoft Corporation | WinXP Powertoy |
| CONTOUR file extension | Mariner Software | Contour Screenplay Format |
| CONTROLS file extension | OpenBVE | OpenBVE Keyboard Settings Format |
| CONVERTERX file extension | SIMX Corporation | SiMX TextConverter Project |
| COO file extension | Autodesk, Inc. | AutoCAD Bounding Coordinates Cookie |
| COOK file extension | N/A | Netscape For Mac Cookie |
| COOL file extension | Sierra Vista Software | QB - Text Analyzer Vocabulary List |
| COORDS file extension | M.Carson | Ribbons Coords |
| COP file extension | N/A | Sam Coupé Sound |
| COPRESET file extension | Phase One | Capture One Preset Format |
| COPY file extension | N/A | Sony Ericsson Protected Content Format |
| COR file extension | Trimble Navigation | Trimble GPS Pathfinder Office Corrected SSF Format |
| COS file extension | Phase One | Creatures Source Code Format |
| COS2 file extension | Pinnacle Systems | Pinnacle Studio Cache Format |
| COSTYLE file extension | Phase One | Capture One Style Format |
| COUNTER file extension | NetObjects Inc. | NetObjects Fusion Components Bbscomp Message |
| COV file extension | Microsoft | Microsoft Cover Page Editor Fax Cover Page Format |
| COVERAGE file extension | Microsoft Corporation | Microsoft Visual Studio Code Coverage |
| COVERAGEXML file extension | Microsoft Corporation | Microsoft Visual Studio Code Coverage |
| COW file extension | Eidos Interactive Ltd. | Thief Game |
| COX file extension | N/A | Click & Create Extension |
| CP file extension | Apple | Xcode C++ Source Code Format |
| CP1 file extension | SINTEF | CARE-S InfoWorks Phosphorus Detail |
| CP2 file extension | ChessBase GmbH | ChessBase Theme Classification |
| CP3 file extension | Microprose | Grand Prix 3 Cockpit Shape Format |
| CP8 file extension | N/A | CP8 256 Gray Scale Image |
| CP9 file extension | N/A | ChoicePoint Encrypted Format |
| CP? file extension | Terry A. Davis | LoseThos C+ Source |
| CPA file extension | Zuken | CADSTAR PCB Archive Format |
| CPB file extension | Comicino Media | Comicino Studio Project Format |
| CPBITMAP file extension | Apple | Apple IPhone Bitmap Wallpaper Format |
| CPC file extension | Cartesian Products | Cartesian Perceptual Compression Compressed Image |
| CPCT file extension | Cyclos | Compact Pro Archive |
| CPD file extension | RGB Light | Compression PhotoDefiner Image Format |
| CPDT file extension | Adobe Systems Incorporated | Adobe Captivate Design Template |
| CPE file extension | Microsoft | Win95 Cover Page Editor Fax Cover Sheet Format |
| CPF file extension | IBM | Cognos Project Format |
| CPG file extension | Smith Micro | Manga Studio Drawing |
| CPGZ file extension | N/A | Compressed UNIX CPIO Archive |
| CPH file extension | Corel | Corel Print House Printing Project Format |
| CPI file extension | Sony | AVCHD Clip Information Format |
| CPIO file extension | N/A | Unix CPIO Archive Format |
| CPK file extension | Microsoft | DTM Test Log Format |
| CPL file extension | Microsoft | Microsoft Windows Control Panel Format |
| CPMZ file extension | Benetech | Miradi Project Format |
| CPN file extension | Microsoft | Age Of Empires Campaign Format |
| CPO file extension | Corel Corporation | Corel Print House Data |
| CPP file extension | N/A | C++ Main Source Code File Format |
| CPQ file extension | Compaq | Compaq OEM Disc Configuration Format |
| CPR file extension | Steinberg Media Technologies | Cubase Project Format |
| CPRR file extension | Adobe Systems Incorporated | Adobe Captivate XML Script |
| CPS file extension | Corel | Corel Photo House Image Format |
| CPT file extension | Corel | Corel PHOTO-PAINT Bitmap Format |
| CPT2 file extension | GForce | M-Tron Pro Library |
| CPTL file extension | Adobe Systems | Adobe Captivate Project Template Format |
| CPTM file extension | Adobe Systems Incorporated | Adobe Captivate Theme |
| CPTX file extension | Adobe Systems | Adobe Captivate Project Format |
| CPU file extension | N/A | Sisoftware Sandra |
| CPX file extension | Oracle | Oracle Application Development Framework ADF Binding Context Format |
| CPY file extension | Nuance Communications | ECopy Desktop Scanned Document Format |
| CPZ file extension | Terry A. Davis | LoseThos C+ Source |
| CQL file extension | SiHiDa and balduz | XDCC Catcher Queue List |
| CQT file extension | IDEAlliance | MAIL.DAT Container Quantity Data |
| CR file extension | Vital Inc | CRiSP Source Code |
| CR1 file extension | Campbell Scientific, Inc. | LoggerNet CRBasic Source |
| CR2 file extension | Canon | Canon Digital Camera RAW Image Format Version 2.0 |
| CR5 file extension | Spectra Precision | Survey Pro Coordinate |
| CRAFT file extension | Squad | KSP Spacecraft Format |
| CRASH file extension | Apple | Apple Mac OS X Console Report Format |
| CRASHED file extension | AbiSource | AbiWord Crash-saved Document Format |
| CRB file extension | BigOven.com | BigOven Recipe Database |
| CRC file extension | Ghisler Software | Total Commander CRC Format |
| CRD file extension | Microsoft | Microsoft Windows Cardfile Database Format |
| CRDOWNLOAD file extension | Google Chrome Incomplete Download Format | |
| CRDS file extension | Microsoft | Microsoft Windows CardSpace Backup Format |
| CREC file extension | Microsoft Corporation | Microsoft Lync 2010 Recording |
| CREOLE file extension | N/A | Creole Source |
| CREV file extension | Adobe Systems | Adobe Captivate Review Format |
| CRF file extension | Cal3D | Cal3D Binary Materials Format |
| CRG file extension | invers Software | Calamus Picture Image |
| CRH file extension | Procedimientos-Uno, S.L. | EN-CC Truss Geometry |
| CRI file extension | SAP AG | Crystal Reports |
| CRL file extension | N/A | Certificate Revocation List |
| CRMLOG file extension | Microsoft Corporation | Microsoft Windows CRM Log |
| CRP file extension | Corel Corporation | CorelDRAW Corel Presents Run-time Presentation |
| CRS file extension | StepMania | StepMania Course Format |
| CRS3 file extension | Nuance Communications, Inc. | OmniPage Lite |
| CRT file extension | N/A | Internet Security Certificate |
| CRTR file extension | MultiAd | MultiAd Creator Pro Document Format |
| CRTX file extension | Microsoft | Microsoft Office 2007 Chart Template Format |
| CRV file extension | Vectric | VCarve Pro Design Format |
| CRW file extension | Canon | Canon Digital Camera RAW Image Format |
| CRWL file extension | Microsoft | Microsoft Windows Crawl Format |
| CRX file extension | Google Chrome Extension Installer File Format | |
| CRY file extension | CRYTEK | CryENGINE Map Format |
| CRYPT file extension | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| CRYPT5 file extension | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| CRYPT6 file extension | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| CRYPT7 file extension | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| CRYPTED file extension | Ashampoo | Ashampoo WinOptimizer Encrypted Format |
| CRYPTOMITE file extension | BAxBEx Software | CryptoMite Encrypted Archive |
| CRYPTRA file extension | BMB Software | Cryptra Encrypted Format |
| CRYSISJMSF file extension | Crytek | Crysis Saved Game Format |
| CRYSISPSF file extension | Crytek | Crysis Warhead Saved Game Position Format |
| CRZ file extension | Smith Micro | Compressed Poser Character Rigging Format |
| CS file extension | Microsoft | Microsoft Visual Studio Visual C#.NET Source Format |
| CS1 file extension | N/A | Sinar CaptureShop |
| CS2 file extension | CyberStep | CyberStep2 |
| CS4 file extension | Sinar | Sinar CaptureShop 4-shot Image |
| CS8 file extension | The Open Group | Unix Graphics Format |
| CSA file extension | Agilent | Agilent PNA Code Calset Format |
| CSAC file extension | macropool GmbH | Web Research Collection Optimization Temporary |
| CSAPLAN file extension | IBM | SPSS Analysis Plan Format |
| CSASSEMBLY file extension | ICQ LLC | ICQ 6 |
| CSATTR file extension | Microsoft Corporation | Microsoft Visual Studio Attractor |
| CSB file extension | Corel Corporation | Corel PHOTO-PAINT Script |
| CSC file extension | Corel Corporation | CorelDRAW Corel SCRIPT Script |
| CSCPKT file extension | Colasoft | Sample Packet |
| CSD file extension | Dream To Reality | Compact Shared Document |
| CSDPROJ file extension | Microsoft Corporation | C# Device Project |
| CSE file extension | macropool GmbH | Web Research Document Package |
| CSF file extension | Informative Graphics | Content Secure Format |
| CSGRAD file extension | Microsoft Corporation | Microsoft Visual Studio Gradients |
| CSH file extension | Adobe Systems | Adobe Photoshop Shapes Format |
| CSHRC file extension | N/A | UNIX Command |
| CSHTML file extension | Microsoft | ASP.Net Web Page |
| CSI file extension | ContentServ | ContentServ CS EMMS Suite Include Format |
| CSJ file extension | BlackBerry (Research In Motion Limited) | RIM CSJ Registration |
| CSK file extension | Apple, Inc. | Claris Works |
| CSKIN file extension | CD Art Display | CD Art Display Skin Format |
| CSL file extension | Technicolor | CineStyle Color Settings Format |
| CSM file extension | Autodesk | 3ds Max Character Studio Maker Format |
| CSMANIFEST file extension | ICQ LLC | ICQ 6 Settings |
| CSML file extension | N/A | Chemical Style Markup Language |
| CSN file extension | Adobe Systems | Adobe Dreamweaver Snippet Format |
| CSO file extension | N/A | CISO Compressed ISO Format |
| CSOM file extension | QUALCOMM Incorporated | Eudora For Mac |
| CSP file extension | RadGs | RadGs Concept Application Server Web Page Format |
| CSPLAN file extension | IBM | SPSS Sampling Plan Format |
| CSPROJ file extension | Microsoft | Microsoft Visual Studio Visual C# Project Format |
| CSQ file extension | Microsoft Corporation | Microsoft FoxPro Queries |
| CSR file extension | N/A | Certificate Signing Request Format |
| CSS file extension | N/A | Cascading Style Sheets Format |
| CSS1 file extension | N/A | Cascading Style Sheet |
| CSSTORE file extension | Apple, Inc. | Apple Mac OS X Cache |
| CST file extension | ContentServ | ContentServ Template |
| CSV file extension | N/A | Comma Separated Value Format |
| CSVIEW file extension | Microsoft Corporation | Microsoft Visual Studio Views |
| CSVX file extension | N/A | XML CSV |
| CSW file extension | Corel Corporation | Corel WordPerfect Setup Information |
| CSX file extension | Microsoft | Microsoft Visual C# Primary Script Format |
| CSY file extension | ACD Systems | Canvas Symbol Library Format |
| CSZ file extension | CoreCodec, Inc. | The Core Media Player Skin |
| CT file extension | Cheat Engine | Cheat Engine Cheat Table Format |
| CT0 file extension | Tajima Group | Tajima TBF Condition |
| CT1 file extension | Microsoft Corporation | SMS Proposed Site Control |
| CT7 file extension | LexisNexis | CaseMap Case Analysis Template |
| CT8 file extension | LexisNexis | CaseMap Case Template |
| CTA file extension | Venstar Inc. | ColorTouch Assistant Settings |
| CTB file extension | Autodesk | AutoCAD Colour-dependent Plot Style Table Format |
| CTBL file extension | N/A | Xamine NSCL |
| CTBODYFITTING file extension | Reallusion | CrazyTalk Animator Format |
| CTC file extension | Naviter d.o.o. | SeeYou Flight Data |
| CTD file extension | NativeWinds LLC | Tomahawk Gold Compressed Tomahawk Document |
| CTE file extension | Stefan Hagel | Classical Text Editor Document |
| CTF file extension | AVG Technologies | AVG Antivirus Update Control Format |
| CTFSYS file extension | N/A | OS X Mach Kernel System |
| CTI file extension | Bitz & Pixelz BV | Collectorz.com Template Info |
| CTIT file extension | N/A | RAR Archive |
| CTK file extension | Procedimientos-Uno, S.L. | TeKton3D Project |
| CTL file extension | Microsoft | Visual Basic Control File (Active X Control File) |
| CTM file extension | Reallusion | Crazy Talk Face Model Format |
| CTMDPI file extension | RWTH Aachen University | MRMC Markov Reward Model Checker Matrix |
| CTN file extension | CADTERNS Custom Clothing Inc | Cadterns Sloper Format |
| CTO file extension | Microsoft Corporation | Microsoft Visual Studio Binary Command Table Output |
| CTP file extension | Cake Software Foundation | CakePHP Template Format |
| CTPROJECT file extension | Reallusion | CrazyTalk Animator Project |
| CTR file extension | Rainer Goebel | BrainVoyager QX Contrast |
| CTS file extension | Reallusion | CrazyTalk Audio Format |
| CTSYM file extension | Microsoft Corporation | Microsoft Visual Studio Command Table Output |
| CTT file extension | Microsoft | Windows Live Messenger Contact List Format |
| CTV file extension | Swiss Academic Software | Citavi Project Format |
| CTV3 file extension | Swiss Academic Software | Citavi 3 Project Format |
| CTX file extension | Microsoft | Visual Basic User Control Binary Format |
| CTXT file extension | University of Kent | BlueJ Information Format |
| CTY file extension | Maxis | SimCity City Format |
| CTZ file extension | Dextronet.com | Custody Toolbox Compressed Backup |
| CU file extension | NVIDIA | CUDA Source Code Format |
| CU1 file extension | Impressum | Photoline 4 Curve |
| CU3 file extension | Impressum | Photoline Curves Clut |
| CU? file extension | Impressum | Photoline Clut |
| CUB file extension | Microsoft | Analysis Services Cube Format |
| CUBE file extension | N/A | Antaeus |
| CUE file extension | N/A | Cue Sheet Description Format |
| CUF file extension | Embarcadero Technologies, Inc. | Turbo C Utilities Form Definition |
| CUI file extension | Autodesk | AutoCAD Customization Format |
| CUIX file extension | Autodesk | Autodesk AutoCAD Custom User Interface Format |
| CUL file extension | N/A | IconForge ImageForge Cursor Library |
| CUP file extension | Naviter d.o.o. | SeeYou Waypoint |
| CUR file extension | N/A | Windows Cursor Format |
| CURRENT file extension | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database |
| CURSEMOD file extension | Curse Inc. | Curse Client Mod |
| CURSOR file extension | N/A | Sun Cursor |
| CURSORFX file extension | Stardock | CursorFX Cursor Theme Format |
| CURXPTHEME file extension | Stardock | CursorFX Theme Format |
| CUS file extension | Autodesk | AutoCAD Custom Dictionary Format |
| CUST file extension | Quark, Inc. | QuarkXPress Mac File Type |
| CUSTOMDESTINATIONS-MS file extension | Microsoft Corporation | Microsoft Windows 7 Jump List |
| CUT file extension | N/A | Dr. Halo Bitmap Format |
| CUTECUTPROJECT file extension | MobiVio Solutions | Cute Cut Project |
| CUV file extension | OriginLab Corporation | Origin Sample Curve |
| CU_ file extension | Microsoft Corporation | Microsoft Windows Winhelp Compressed |
| CV file extension | N/A | Microsoft CodeView Information Screen |
| CV5 file extension | ACD Systems | Canvas 5 Drawing Format |
| CVA file extension | Hewlett-Packard | HP Compaq Diagnostics Format |
| CVC file extension | N/A | CVideo Format |
| CVD file extension | Sourcefire | Clam AntiVirus Database Format |
| CVF file extension | CPUID | CPU-Z Validation Format |
| CVG file extension | invers | Calamus Vector Image File Format |
| CVI file extension | ACD Systems | Canvas Vector Image Format |
| CVM file extension | ATLUS | Odin Sphere |
| CVN file extension | Sonic Solutions | Sonic CineVision Encoding Session Format |
| CVP file extension | N/A | Portrait Image Format |
| CVR file extension | Microsoft | Microsoft Office Crash Report Format |
| CVS file extension | ACD Systems | CVS And VMS Sound Files (continous Variable Slope) |
| CVSIGNORE file extension | N/A | Eclipse CVS Settings |
| CVSRC file extension | N/A | TortoiseCVS CVS Command |
| CVT file extension | ACD Systems | Canvas External Tool Format |
| CVW file extension | CaseWare | CaseView Document Format |
| CVX file extension | ACD Systems | Canvas Drawing Format |
| CVZ file extension | Lone Wolf Development, Inc. | Card Vault Inventory |
| CW file extension | NCH Software | CardWorks Template Format |
| CW3 file extension | N/A | Claris Works Document |
| CW7 file extension | Codeware, Inc. | COMPRESS Related |
| CWB file extension | Cakewalk | Cakewalk Bundle |
| CWC file extension | ITI TranscenData | CADfix Wizard Configuration |
| CWDB file extension | Apple, Inc. | ClarisWorks Database |
| CWF file extension | Corel | CorelDRAW Workspace Format |
| CWGR file extension | Apple, Inc. | ClarisWorks Drawing |
| CWIE file extension | Freescale Semiconductor, Inc. | CodeWarrior |
| CWK file extension | Apple | ClarisWorks Document Format |
| CWKS file extension | Apple, Inc. | ClarisWorks |
| CWL file extension | Apple, Inc. | ClarisWorks Library |
| CWLINK file extension | Freescale Semiconductor, Inc. | CodeWarrior |
| CWM file extension | IBM | WebSphere Map Designer Express Map Definition |
| CWMS file extension | CompeGPS TEAM S.L. | CompeGPS Land Remote Map |
| CWP file extension | Cakewalk | Cakewalk Sonar Audio Project Format |
| CWPT file extension | Apple, Inc. | ClarisWorks Painting Drawing |
| CWR file extension | SAP AG | Crystal Reports Report |
| CWS file extension | Apple | ClarisWorks Template Format |
| CWSS file extension | Apple, Inc. | ClarisWorks Spreadsheet |
| CWT file extension | ClarisWorks | ClarisWorks Texture Format |
| CWW file extension | Variety Games | Crossword Weaver Format |
| CWWP file extension | Apple, Inc. | ClarisWorks Document |
| CWX file extension | Cakewalk, Inc. | Sonar Track Template |
| CWZ file extension | New Wave Concepts Limited | Circuit Wizard Format |
| CW_ file extension | Corel Corporation | CorelDRAW Workspace |
| CX file extension | Orbitech Ltd. | CodeMapper Script |
| CX3 file extension | IDView | CMS Video Format |
| CXA file extension | ANSYS Inc. | ANSYS Fluent Animation Metadata |
| CXARCHIVE file extension | CodeWeavers Inc. | CrossOver Bottle |
| CXB file extension | Custody X Change | Custody X Change Data |
| CXD file extension | Hamamatsu Photonics | SimplePCI Graphics Data Format |
| CXE file extension | N/A | Common XML Envelope |
| CXF file extension | Google Picasa Collage Format | |
| CXL file extension | Pervasive Software Inc. | Business Integrator Extract Schema |
| CXML file extension | Microsoft Corporation | Microsoft Silverlight Server Side Data |
| CXP file extension | OMRON | Omron CX Programmer Format |
| CXQ file extension | N/A | SillyDl.CXQ Downloading Trojan |
| CXR file extension | Omron Corporation | CX-Programmer Settings |
| CXT file extension | Adobe Systems | Adobe Director Protected Cast Format |
| CXV file extension | Custody X Change | Custody X Change Data |
| CXX file extension | N/A | C++ Main Source Code File Format |
| CYA file extension | CYANA Development Team | Cyana Macro |
| CYBERDUCKLICENSE file extension | Cyberduck | Cyberduck For Mac OS License Format |
| CYBERDUCKPROFILE file extension | Cyberduck | Cyberduck Connection Profile |
| CYI file extension | Hot Neuron | Clustify Input Format |
| CYL file extension | M.Carson | Ribbons Cylinder |
| CYO file extension | Hot Neuron | Clustify Output Format |
| CYP file extension | Chief Architect | Home Designer Pro Project Format |
| CYR file extension | CRYTEK | Crysis Level |
| CYS file extension | Hot Neuron | Clustify Summary Statistics Format |
| CYW file extension | N/A | Rbot.CYW Worm Format |
| CZ file extension | N/A | Czech Language Translation |
| CZD file extension | The CAD Zone | The Crash Zone Drawing Format |
| CZI file extension | Carl Zeiss | Carl Zeiss Image Data Format |
| CZIP file extension | WinInizio Software | ZG Encrypted Zip Archive |
| CZN file extension | N/A | RMCProfile Atom List |
| CZP file extension | Crick Software | ClozePro Archive Format |
| C_ file extension | Microsoft Corporation | Microsoft Winhelp Compressed |
| C__ file extension | N/A | C++ Source Code |
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