| cpv | Serena PVCS Logfile |
| cpw | GP-Pro EX Library |
| cpx | Character Set Translation Table |
| cpx | CorelDraw Exchange Compressed Drawing |
| cpxml | IBM ABLE Conversation Policies XML |
| cpy | Autodesk 3D Studio Max Copy Track Data |
| cp_ | Compressed CPL File |
| cq | CP/M SYSGEN Replacement Data |
| cqcn | Chimera Tool Data |
| cqe | Cumulus 6 Query Export Data |
| cqf | PCAnywhere Command Queue Data |
| cql | XDCC Catcher Queue List |
| cqs | ConQuest Saved Search File |
| cqt | Mail.dat Container Quantity Data |
| cr0 | Autodesk Moldflow Cool Analysis Restart File |
| cr2 | Poser Character |
| cr3 | Casio WK-1800 Registration Data |
| cr4 | STABCAL Calculation Data |
| cram | CRAM Data |
| crash | Steam Crash Data |
| crashed | AbiWord Crash-Saved Document |
| crate | Serato DJ Crate Data |
| crc32 | CRC32 Checksum |
| crd | CARE-S InfoWorks Catchment Runoff Data |
| crd | Carlson 2016 Coordinate Data |
| crd | CHARTrunner Dashboard |
| crd | MODELLER Atom Coordinates CHARMM Data |
| crdb | Carlson 2016 Coordinate Database |
| crds | Windows CardSpace Backup |
| creole | Creole Source Code |
| crf | Cal3D Binary Materials Data |
| crf | MOUSE Runoff Data |
| crf | Sierra Print Artist Craft Data |
| crg | OpenCRG Data File |
| cri | PLS-CADD Criteria |
