| cm0012 | WD TV Live Corrupt Data |
| cng | C-NaviGator Software Update |
| cng3 | C-NaviGator Software Update |
| cn_ | Compressed Windows Help Content |
| component | Mac OS X System Component |
| con | OASIS Montaj Control File |
| conv | Stylus Studio Data User-defined Converter |
| cos2 | Pinnacle Studio Cache |
| cpq | Compaq OEM Disc Configuration |
| crc | CRC Checksum |
| crd | Microsoft Windows Cardfile |
| crdownload | Chrome Partially Downloaded File |
| crp | LG 2-3G Tool Firmware |
| crp1 | LG 2-3G Tool Firmware |
| crplugin | ComicRacks Plugin |
| crt | Certificate File |
| csr | Certificate Signing Request |
| csu | Crestron Software Update |
| cuj | Personal Backup Saved Task |
| cursemod | Curse Client Mod |
| cvr | Microsoft Crash Report |
| cvt | ACDSee Canvas External Tool |
| cxn | Conexant Modem Driver |
| cya | CYANA Macro File |
| d2a | AviSynth MPASource Plug-in |
| d5c | Dragon UnPACKer Plugin |
| d5d | Dragon UnPACKer Driver |
| dbase | Aston-Tate dBASE Database |
| dbf | Aston-Tate dBASE Database |
| der | Certificate File |
