| C | C Program File |
| C | Check Point Site Configuration for Secure Remote |
| C | Desktop Color Separation Specification Cyan Layer |
| C?? | Winace Compressed File |
| C++ | C++ Source Code |
| C-- | Sphinx C-- Source code |
| C__ | C++ Source Code |
| C00 | Ventura Print File |
| C01 | Typhoon Wave File |
| C2D | WinOnCd CD Image |
| C3D | Micrografx |
| C86 | C86 C Program |
| CA | Telnet Server Initial Cache Data File |
| CA7 | Beta 44 Job File |
| CAB | Cabinet File (Microsoft installation archive) |
| CAB | Install Shield v5.x or 6.x Compressed File |
| CAC | Microsoft Infoview |
| CAC | dBase IV Executable File |
| CAD | Softdesk Drafix CAD File |
| CAG | MS Clip Gallery Catalog File |
| CAL | Microsoft Schedule Plus 1.0 |
| CAL | CALS Compressed Bitmap |
| CAL | Calendar File |
| CAL | SuperCalc Worksheet |
| CAM | Casio Camera Graphic |
| CAN | Navigator Fax |
| CAP | Ventura Publisher Caption |
| CAP | Telix Session Capture |
| CAP | Compressed Music File |
| CAP | Network Associates Sniffer Capture File |
| CAR | AtHome Assistant File |
| CAS | Comma Separated Text File |
| CAS | Netica Comma Separated Value Text File of Cases (http://www.norsys.com) |
| CAS | Borland combined C/Assembly source code |
| CAS | Casio Program |
| CAT | dBase IV Catalog |
| CAT | Quicken IntelliCharge Categorization File |
| CAZ | Computer Associates Archive |
| CB | MS Clean Boot File |
| CBC | CubiCalc Fuzzy Logic System File |
| CBI | IBM Mainframe Column Binary Formatted File |
| CBL | COBOL Program |
| CBM | XLib Compiled Bitmap |
| CBT | Computer Based Training |
| CC | C++ Program File |
| CC | Visual dBASE Custom Class File |
| CC5 | Calendar Creator 5.x 6.x File |
| CCA | Click 'n Create data |
| CCA | CC:Mail File |
| CCB | Visual Basic Animated Button Configuration |
| CCC | Chat |
| CCC | Curtain Call Native Bitmap Graphic |
| CCD | CloneCd Related File |
| CCD | Vector CAD Program File |
| CCE | Calendar Creator Plus Data File |
| CCF | Symphony Communications Configuration File |
| CCF | OS/2 Multimedia Viewer Configuration File |
| CCH | Corel Chart |
| CCL | Intalk Communication Command Language |
| CCM | Lotus CC:Mail Mailbox |
| CCO | CyberChat data file |
| CCR | Chat Room Shortcut |
| CCT | Macromedia Director Shockwave Cast |
| CCX | Corel Compressed Exchange File |
| CDA | CD Audio Track |
| CDB | Turbo C Database |
| CDB | CardScan Database |
| CDB | Clipboard File |
| CDB | PowerDesigner Conceptual Model Backup File |
| CDB | SymbianOS Contact Database File |
| CDC | Nero File |
| CDD | Claris Draw v 1.2 Document |
| CDF | MS Channel Definition Format |
| CDF | Comma Delimited Format |
| CDF | Cyberspace Description Format |
| CDF | InstallShield Components Definition File |
| CDI | Phillips Compact Disk Interactive Format |
| CDK | Atari Calamus Document |
| CDM | PowerDesigner Conceptual Model File |
| CDM | Visual dBASE Custom Data Module |
| CDR | Corel Vector Graphic |
| CDR | Raw Audio-CD Data |
| CDT | Corel Draw Template |
| CDX | Corel Draw Compressed Drawing |
| CDX | MS Visual Foxpro Index |
| CDX | Compound Index |
| CDX | Active Server Document |