| 1 | C | N/A | C/C++ Source Code Format |
| 2 | C# | N/A | Microsoft Visual C# data |
| 3 | C++ | N/A | Generic |
| 4 | C00 | e-merge | WinAce Split Archive Format |
| 5 | C01 | e-merge | WinAce Split Archive Part 1 Format |
|
| 6 | C02 | e-merge | WinAce Split Archive Part 1 Format |
| 7 | C03 | e-merge GmbH | Split Multi-volume ACE Compressed Format Archive |
| 8 | C04 | N/A | Split Multi-volume ACE Compressed Format Archive |
| 9 | C2D | Roxio | WinOnCD Disc Image |
| 10 | C3D | ADTech | Coordinate 3D Format |
| 11 | C3E | N/A | CYPE Related |
| 12 | C4D | MAXON Computer | Cinema 4D Model Format |
| 13 | C6 | Ashlar Incorporated | Organic 2D/3D Drafting & 3D Modelling |
| 14 | C64 | N/A | Commodore 64 ROM Image |
| 15 | C85 | RISCOS Ltd. | RISC OS JPEG Bitmap Image |
| 16 | CA | N/A | Initial Telnet Cache |
| 17 | CAB | Microsoft | Windows Cabinet Format |
| 18 | CACHE | N/A | Cache Format |
| 19 | CACTION | Apple | Automator Converter Action |
| 20 | CAD | BobCAD-CAM | BobCAD-CAM Format |
| 21 | CAF | Apple | Core Audio Format |
| 22 | CAFF | Apple | Core Audio Format |
| 23 | CAG | Microsoft | ClipArt Gallery Package |
| 24 | CAL | Autodesk | 3ds Max Pose Adjustment Format |
| 25 | CAM | Ucamco | Gerber CAM Job Format |
| 26 | CAMV | TechSmith | Camtasia Video Format |
| 27 | CANNEDSEARCH | Apple, Inc. | Apple Mac OS X Finder Predefined Search |
| 28 | CAP | N/A | Packet Capture Format |
| 29 | CAPFILE | Ruby community | Ruby Capistrano Instruction |
| 30 | CAR | N/A | Car Explorer Data Format |
| 31 | CAS | Autodesk | Autodesk AutoCAD License Format |
| 32 | CASCII | N/A | CACTVS Chemical ASCII Format |
| 33 | CATDRAWING | Dassault Systèmes S.A. | CATIA Drawing |
| 34 | CATPART | Dassault Systemes | CATIA V5 Part Format |
| 35 | CATPRODUCT | Dassault Systemes | CATIA V5 Assembly Format |
| 36 | CATSHAPE | Dassault Systèmes S.A. | CATIA Shape |
| 37 | CAX | Visual Collaboration Technologies Inc. | VCollab 3D Model |
| 38 | CA_ | N/A | Microsoft Cabinet archive |
| 39 | CB7 | N/A | Comic Book 7-Zip Archive |
| 40 | CBD | Corel Corporation | Corel WordPerfect Dictionary |
| 41 | CBDS | Nicom00k | Comic Book DS Format |
| 42 | CBF | Tailwag Software | Calendar Builder Format |
| 43 | CBL | N/A | COBOL Source Code Format |
| 44 | CBO | Microsoft Corporation | Microsoft Interactive Training |
| 45 | CBPROJ | Embarcadero Technologies, Inc. | C++ Builder Project |
| 46 | CBR | N/A | Comic Book Archive Format Or ComicBook Reader Format |
| 47 | CBT | Microsoft | CDisplay TAR Comic Book Format |
| 48 | CBZ | N/A | Comic Book Archive Format Or ComicBook Reader Format |
| 49 | CC | N/A | C++ Source Code Format |
| 50 | CCC | Microsoft Corporation | Microsoft Internet Chat Conversation Log |
| 51 | CCD | SlySoft | CloneCD Disc Image |
| 52 | CCGAME | Microsoft | XNA Creators Club Game Package |
| 53 | CCN | Clickteam | Multimedia Fusion Development Format |
| 54 | CCT | Adobe Systems | Director Protected Cast Resource |
| 55 | CCX | Clickteam | Click & Create Extension |
| 56 | CCXML | N/A | Call Control EXtensible Markup Language |
| 57 | CDA | N/A | CD Audio Track |
| 58 | CDATA | Electronic Arts, Inc. | Command & Conquer 3 Audio |
| 59 | CDDA | N/A | CD Digital Audio Format |
| 60 | CDG | N/A | DART Karaoke Studio Lyrics Format |
| 61 | CDI | Padus | DiscJuggler Disc Image |
| 62 | CDLX | Adobe Systems | Audition CD Layout Format |
| 63 | CDMM | Computer Systems Odessa | ConceptDraw MINDMAP Document |
| 64 | CDMZ | Computer Systems Odessa | Compressed ConceptDraw MINDMAP Document |
| 65 | CDR | Corel | CorelDRAW Image Format |
| 66 | CDT | Corel | CorelDRAW Image Template |
| 67 | CDU | N/A | CDU Paint Image Format |
| 68 | CE0 | N/A | Winewar Worm |
| 69 | CEDF | N/A | Ultra TC Editors Data File |
| 70 | CEID | N/A | Seagate Dockstar configuration |
| 71 | CEKEY | N/A | McAfee VirusScan configuration |
| 72 | CEO | N/A | Winewar Worm |
| 73 | CETRAINER | Cheat Engine | DBVM |
| 74 | CF | N/A | Sendmail Configuration Format |
| 75 | CFA | Adobe Systems | Adobe Conformed Audio Format |
| 76 | CFC | Adobe Systems | ColdFusion Component Format |
| 77 | CFG | N/A | Configuration Format |
| 78 | CFGE | iWin | Jewel Quest Configuration Format |
| 79 | CFM | Adobe Systems | ColdFusion Markup Format |
| 80 | CFML | Adobe Systems | ColdFusion Markup Language Format |
| 81 | CFXXE | N/A | Possibly Malware |
| 82 | CFZ | N/A | Compressed Archive |
| 83 | CG | NVIDIA | Cg Program |
| 84 | CGI | N/A | Common Gateway Interface Script |
| 85 | CGM | N/A | Computer Graphics Metafile |
| 86 | CGR | Dassault Systemes | CATIA Graphical Representation Format |
| 87 | CGVP | NVIDIA Corporation | NVidia Cg Programming Language XML |
| 88 | CGX | ARM Holdings plc | ARM RL-TCPnet HTTP Web Server XML Web Page Update Script |
| 89 | CH3 | Harvard Graphics | Harvard Graphics DOS Chart Format |
| 90 | CH6 | N/A | ZX-Paintbrush character |
| 91 | CH8 | N/A | Generic |
| 92 | CHA | N/A | IRC Chat Configuration Format |
| 93 | CHARSET | N/A | Character Set |
| 94 | CHG | Intuit Inc | Quicken Online Data Format |
| 95 | CHH | N/A | C++ Header |
| 96 | CHI | Microsoft Corporation | Microsoft Help Index |
| 97 | CHK | Microsoft | ScanDisk Format Fragment |
| 98 | CHL | Microsoft | Microsoft Internet Explorer Channel Information Format |
| 99 | CHM | Microsoft | Compiled HTML Help Format |
| 100 | CHML | Krasbit Technologies | Chameleon Encrypted Database Format |
| 101 | CHORD | N/A | Song Chords Format |
| 102 | CHR | Autodesk | 3ds Max Characters Format |
| 103 | CHS | Microsoft | Windows Chinese Noise-Word List Format |
| 104 | CHTML | N/A | Compact HTML Document |
| 105 | CHU | N/A | Infinity Engine user interface description |
| 106 | CHX | Autodesk | AutoCAD Standards Check Format |
| 107 | CIDB | Apple | Apple ITunes CD Information Format |
| 108 | CIE | N/A | Generic |
| 109 | CIH | N/A | Generic |
| 110 | CIN | Kodak | Kodak Cineon Bitmap Format |
| 111 | CINE | Vision Research | Phantom Digital Video Format |
| 112 | CIP | Cavena | CryptoBuddy Encrypted Format |
| 113 | CISO | N/A | Wii Compressed Game Image |
| 114 | CIT | Intergraph | Intergraph Bitmap Image Format |
| 115 | CKD | Kubotek | CADKEY Design Format |
| 116 | CKM | N/A | Creation Kit macro |
| 117 | CL | Aha-Soft | Cursor Library |
| 118 | CLAM | Adobe Systems Incorporated | Adobe InDesign Dictionary |
| 119 | CLASS | Oracle | Java Class Format |
| 120 | CLEO | CLEO | CLEO Grand Theft Auto Mod Format |
| 121 | CLIPPING | Apple, Inc. | Apple Mac OS X Finder |
| 122 | CLJ | N/A | Clojure Source Code |
| 123 | CLOJURE | N/A | Clojure source code |
| 124 | CLP | Reallusion | CrazyTalk Clip Format |
| 125 | CLR | Adobe Systems | Flash Color Set |
| 126 | CLS | N/A | LaTeX Document Class Format |
| 127 | CLSID | N/A | Generic |
| 128 | CLW | Microsoft | Visual C++ ClassWizard Format |
| 129 | CLX | Adobe Systems | Standard Dictionary Format |
| 130 | CM | Rockstar Games | CLEO Custom Mission |
| 131 | CM0013 | Samsung | Samsung Smart TV Index File |
| 132 | CM2 | Smith Micro | Poser Camera Set Format |
| 133 | CM5 | Sci-Ed | LexisNexis Case Analysis |
| 134 | CMAKE | Kitware, Inc. | CMake Module |
| 135 | CMB | Jeffrey C Johnson (XTree Company) | Xtree For Windows Button Bar |
| 136 | CMD | Microsoft | Windows Command Format |
| 137 | CMF | Creative Labs | Creative Labs FM-synthesis Music Format |
| 138 | CMT | N/A | Chinon ES-1000 Digital Camera Image Format |
| 139 | CMTX | Rick Meyers | E-Sword Commentary |
| 140 | CMX | Corel | Corel Metafile Exchange Image Format |
| 141 | CMZ | Smith Micro | Compressed Poser Camera Set Format |
| 142 | CN | Procedimientos-Uno, S.L. | CNwin/MLwin Account |
| 143 | CNF | MySQL | MySQL Configuration Format |
| 144 | CNN | N/A | ADO-network Connection Configuration |
| 145 | CNT | Microsoft | Help Contents Format |
| 146 | CNV | ACD Systems | Canvas 6-8 Drawing Format |
| 147 | COA | Caligari Corporation | Caligari TrueSpace 3D Object |
| 148 | COB | N/A | COBOL Source Code Format |
| 149 | COD | N/A | Compiled Source Code |
| 150 | COF | Autodesk | AutoDesk Data Format |
| 151 | COFFEE | N/A | CoffeeScript JavaScript Format |
| 152 | COL | Phase One | Capture One Session Format |
| 153 | COLLECTION | Adobe Systems | Adobe Bridge Collection Format |
| 154 | COLLISIONMESH | Electronic Arts, Inc. | Battlefield Collision Mesh |
| 155 | COLZ | Adobe Systems | Adobe Collage Format |
| 156 | COM | Microsoft | DOS Command Format |
| 157 | COMMAND | Apple | Terminal Command Format |
| 158 | COMMON | Apple, Inc. | Unix Script |
| 159 | COMPONENT | Apple | Mac OS X System Component |
| 160 | COMPONENTS | Apple, Inc. | Mac OS X System |
| 161 | CONF | N/A | Configuration Information Format |
| 162 | CONFIGURE | The Open Group | Bash |
| 163 | CONTACT | Microsoft | Windows Contact File |
| 164 | CONTAINER | N/A | Eclipse project settings |
| 165 | CONTENTS | Apple, Inc. | MAC OS X |
| 166 | COO | Autodesk, Inc. | AutoCAD Bounding Coordinates Cookie |
| 167 | COOKIEDB | N/A | Unknown file extension |
| 168 | CP | Apple | Xcode C++ Source Format |
| 169 | CPA | Adobe | Adobe Premiere Conformed Audio Format |
| 170 | CPAA | Adobe Systems | Captivate Shared Action File |
| 171 | CPBITMAP | Apple | IOS Wallpaper Image |
| 172 | CPC | Cartesian Products | CPC Compressed Image Format |
| 173 | CPF | IBM | Cognos Project Format |
| 174 | CPGZ | N/A | Compressed CPIO Archive |
| 175 | CPHD | CloudChan | CloudChan Pre-processed Hypertext Document |
| 176 | CPI | Sony | AVCHD Video Clip Information Format |
| 177 | CPIO | N/A | Unix CPIO Archive |
| 178 | CPL | Microsoft | Windows Control Panel Item |
| 179 | CPLIST | N/A | GNU makefile |
| 180 | CPP | Standard C++ Foundation | C++ Source Code Format |
| 181 | CPT | Corel | Corel Photo-Paint Document |
| 182 | CPTX | Adobe Systems | Adobe Captivate Project Format |
| 183 | CPUPROFILE | N/A | Google Chrome DevTools data |
| 184 | CPVC | Adobe Systems | Adobe Captivate Video Composition |
| 185 | CPX | Oracle | Oracle ADF Binding Context Format |
| 186 | CR2 | Canon | Canon Raw Image Format |
| 187 | CRASH | Apple | Mac OS X Crash Log Format |
| 188 | CRD | Microsoft | Windows CardSpace Format |
| 189 | CRDOWNLOAD | Google | Chrome Partially Downloaded Format |
| 190 | CRDS | Microsoft | Windows CardSpace Backup Format |
| 191 | CRE | N/A | Infinity Engine Creature |
| 192 | CRF | Alexandre Devilliers | Enhanced Dark Engine Game Archive Format |
| 193 | CRG | invers Software | Calamus Picture Image |
| 194 | CRL | N/A | Certificate Revocation List Format |
| 195 | CRS | Corel Corporation | Corel WordPerfect Conversion Resource Format |
| 196 | CRT | N/A | Security Certificate |
| 197 | CRTX | Microsoft | Office 2007 Chart Template Format |
| 198 | CRV | Corel Corporation | CorelDRAW Corel PHOTO-PAINT 10 Custom Gradients Format |
| 199 | CRW | Canon | Canon Raw CIFF Image Format |
| 200 | CRX | Google | Chrome Extension |
| 201 | CRY | Crytek | CryENGINE Map Format |
| 202 | CRYPT | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| 203 | CRYPT10 | WhatsApp | WhatsApp Encrypted Database File |
| 204 | CRYPT11 | N/A | WhatsApp Messenger encrypted message database backup |
| 205 | CRYPT12 | WhatsApp | WhatsApp Encrypted Database File |
| 206 | CRYPT14 | WhatsApp | WhatsApp Encrypted Database File |
| 207 | CRYPT15 | WhatsApp | WhatsApp Encrypted Database File |
| 208 | CRYPT5 | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| 209 | CRYPT6 | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| 210 | CRYPT7 | WhatsApp Inc. | WhatsApp Messenger Encrypted Message Database Backup |
| 211 | CRYPT8 | WhatsApp | WhatsApp Encrypted Database File |
| 212 | CRYPT9 | WhatsApp | WhatsApp Encrypted Database File |
| 213 | CRYPTOWALL | N/A | Encrypted file by Cryptowall ransomware |
| 214 | CRZ | Smith Micro | Compressed Poser Character Rigging Format |
| 215 | CS | Microsoft | Visual C# Source Code Format |
| 216 | CS1 | Sinar | Sinar CaptureShop |
| 217 | CS8 | The Open Group | Unix Graphics Format |
| 218 | CSASSEMBLY | ICQ LLC | ICQ 6 |
| 219 | CSB | Corel Corporation | Corel PHOTO-PAINT Script |
| 220 | CSC | ValuSoft | 18 Wheels Of Steel: Pedal To The Metal Game |
| 221 | CSF | Informative Graphics | Content Sealed Format |
| 222 | CSH | Adobe Systems | Photoshop Custom Shapes Format |
| 223 | CSHP | N/A | ESRI ArcView shape data |
| 224 | CSHRC | N/A | UNIX Command |
| 225 | CSHTML | Microsoft | ASP.NET Razor Web Page |
| 226 | CSJ | BlackBerry (Research In Motion Limited) | RIM CSJ Registration |
| 227 | CSM | Autodesk | Character Studio Marker Format |
| 228 | CSMANIFEST | ICQ LLC | ICQ 6 Settings |
| 229 | CSN | Adobe Systems | Adobe Code Snippet Document |
| 230 | CSO | N/A | CISO Compressed ISO Format |
| 231 | CSON | N/A | Generic |
| 232 | CSPROJ | Microsoft | Visual Studio C# Project |
| 233 | CSS | W3C | Cascading Style Sheet |
| 234 | CSS1 | N/A | Cascading Style Sheet |
| 235 | CSSTORE | Apple, Inc. | Apple Mac OS X Cache |
| 236 | CSV | N/A | Comma Separated Values Format |
| 237 | CSVX | N/A | XML CSV |
| 238 | CSW | Corel Corporation | Corel WordPerfect Setup Information |
| 239 | CSX | Microsoft | Visual C# Script |
| 240 | CTFSYS | N/A | OS X Mach Kernel System |
| 241 | CTP | Cake Software Foundation | CakePHP Template |
| 242 | CTX | Valve | Valve ICE Encoded Script |
| 243 | CUB | Microsoft | Analysis Services Cube Format |
| 244 | CUE | N/A | Cue Sheet Format |
| 245 | CUI | Autodesk | Autodesk Custom Workspace Format |
| 246 | CUR | N/A | Windows Cursor |
| 247 | CURSORFX | Stardock | CursorFX Theme Format |
| 248 | CURXPTHEME | Stardock | CursorXP Theme Format |
| 249 | CUSTOMDESTINATIONS-MS | Microsoft Corporation | Microsoft Windows 7 Jump List |
| 250 | CUT | N/A | Dr. Halo Bitmap Image Format |
| 251 | CU_ | Microsoft Corporation | Microsoft Windows Winhelp Compressed |
| 252 | CVA | Hewlett-Packard | HP Systems Software Manager Information Format |
| 253 | CVR | Microsoft | Microsoft Crash Report Format |
| 254 | CVX | ACD Systems | Canvas Drawing Format |
| 255 | CWK | Apple | ClarisWorks Document |
| 256 | CW_ | Corel Corporation | CorelDRAW Workspace |
| 257 | CXE | N/A | Common XML Envelope |
| 258 | CXML | Microsoft Corporation | Microsoft Silverlight Server Side Data |
| 259 | CXQ | N/A | SillyDl.CXQ Downloading Trojan |
| 260 | CXT | Adobe Systems | Director Protected Cast Format |
| 261 | CXX | N/A | C++ Source Code Format |
| 262 | CYW | N/A | Rbot.CYW Worm Format |
| 263 | CZ | N/A | Czech Language Translation |
| 264 | CZE | N/A | Czech language localization |
| 265 | CZI | Carl Zeiss | Carl Zeiss Image Data Format |
| 266 | CZIP | WinInizio Software | ZipGenius CryptoZip Format |
| 267 | C__ | N/A | C++ Source Code |
