| ctbl | Xamine Data |
| ctd | Cherrytree XML Data |
| ctf | ECMG Content Transformation File |
| cti | Collectorz.com Template Info File |
| ctlg | elcoCAD Catalog Data |
| ctmdpi | MRMC Rate Matrix Data |
| ctn | CADTERNS Sloper |
| ctpx | Microvellum Cut Parts File |
| ctr | BrainVoyager QX Contrast Data |
| cts | GodswMobile Contacts Transfer Backup |
| ctt | MSN Messenger Contact List |
| ctx | CyberTracker Exported Data |
| ctz | Cherrytree Password Protected Data |
| cu1 | PhotoLine 4 Curve Data |
| cub | ISIS 2 Cube |
| cub | Gaussian Cube Data |
| cube | Gaussian Cube Data |
| cud | ChmUpDate Data |
| cuix | Autodesk AutoCAD Custom User Interface |
| cul | Windows Cursor Library |
| cup | Naviter SeeYou Waypoint Data |
| cur | Oasys T/HIS Curve File |
| cursorfx | CursorFX Theme |
| curv | Genetica Mathematical Curve |
| curve | ANSYS TurboGrid Curve File |
| cus | Autodesk AutoCAD Custom Dictionary |
| cus | WindLDR Custom Monitor Data |
| cuts | TS-Doctor Cuts Data |
| cuw | Toyota Calibration Update Wizard Data |
| cva | ACDSee Canvas Sequence Set |
| cvd | Bitdefender Antivirus Database |
| cvd | ClamAV Virus Database |
| cvf | CPU-Z Validation |
| cvj | Cabinet Vision Solid Job |
| cvj | Corticon Vocabulary Data |
