| catsystem | CATIA Functional Systems Data |
| cav | Kintraks Database |
| caw | SSIS Cache Data |
| cb1 | CARE-S InfoWorks Biochemical Oxygen Detail Data |
| cb3 | CliBench Mk III Data |
| cb4 | Actuate Analytics Cube Data |
| cb5 | CubeAnimator LED Data |
| cba | DB/TextWorks SQL Textbase Definition |
| cbb | DB/TextWorks SQL Textbase Structure Definition |
| cbc | MODFLOW Cell-by-cell Flow Data |
| cbg | CyberGauge Data File |
| cbin | CACTVS Binary File |
| cbk | DYMO CardScan Backup Data |
| cbml | Vernier Logger Pro Data |
| cbmv | Comic Book Millennium Collection Data |
| cbo | Microsoft Interactive Training Bookmark |
| cbor | Concise Binary Object Representation Data |
| cbs | DB/TextWorks SQL Textbase Structure Data |
| cbx | IBM Rational XDE Collaboration File |
| cc | STK City Database Counties |
| cc3 | CUEcards Data |
| cc4 | Crossword Compiler v4 Crossword Data |
| cca | cc:Mail Archive |
| ccad | Claris CAD Data |
| ccc | Microsoft Comic Chat Conversation Data |
| ccd | SmartWare Compiled Cartridge Descriptor |
| cce | Cumulus 6 Category Export Data |
| ccf | Cryptload Container Format File |
| cch | .NET Security Cache |
| ccj | Corticon Server Rulesets Data |
| ccj | Compiled Crossword Applet |
| cck | COMcheck Data |
| ccl | CFX CCL File |
| ccm | Multimedia Fusion Custom Menu Data |
| ccm | Lotus CC:Mail |