| co_ | Compressed COM File |
| cp1 | CARE-S InfoWorks Phosphorus Detail Data |
| cp4 | Adobe Captivate 4.0 Simulation Data |
| cpa | Cadstar PCB Design |
| cpaa | Adobe Captivate Shared Action Data |
| cpd | Adobe RoboHelp Cache Project Database |
| cpg | CATS PG File |
| cpglog | Motorola Codeplug Session Log |
| cpi | Lifo-Pro Consumer Price Index |
| cpi | MS-DOS Code Page Information |
| cpixml | iTWO Construction Process Integration XML |
| cpl | TINA Complex Parameter List |
| cpl | Tekla Structures Contour Plate Properties |
| cprr | Adobe Captivate XML Recording Script |
| cpt | Casio WK-1800 Pattern Sequerncer Pattern |
| cpt | Ccrypt Encrypted File |
| cpt | Mail.dat Component File |
| cpt2 | M-Tron Pro Library |
| cptl | Adobe Captivate 5 Template |
| cptm | Adobe Captivate Theme Data |
| cpu | SiSoftware Sandra File |
| cpv | Serena PVCS Logfile |
| cpw | GP-Pro EX Library |
| cpx | Character Set Translation Table |
| cpxml | IBM ABLE Conversation Policies XML |
| cp_ | Compressed CPL File |
| cqcn | Chimera Tool Data |
| cqe | Cumulus 6 Query Export Data |
| 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 |
| crate | Serato DJ Crate Data |
| crc32 | CRC32 Checksum |