| ctx | Gasteiger Group CTX Chemical Data |
| ctx | Nokia PC Suite Contacts Backup |
| ctx | Pretty Good Privacy Cipher Text Data |
| cty | Fog Creek CityDesk Template Data |
| ctz | Cherrytree Password Protected Data |
| ctz | EFILive Calibration Tune Data |
| cu | 1C:Enterprise Configuration Update Data |
| cu | CU-SeeMe Data |
| cu | my Knowledge Explorer Change Unit |
| cu1 | PhotoLine 4 Curve Data |
| cu3 | PhotoLine 4 Curve Data |
| cub | Cubloc Studio PLC Data |
| cub | Gaussian Cube Data |
| cub | IBM Cognos PowerPlay Cube Data |
| cub | ISIS 2 Cube |
| cub | Microsoft SQL Server Analysis Services Cube Data |
| cub | Microsoft Windows Installer Validation Module |
| cube | Gaussian Cube Data |
| cuce | CU-SeeMe Data |
| cud | ChmUpDate Data |
| cudt | ClarisWorks User Dictionary Data |
| cuix | Autodesk AutoCAD Custom User Interface |
| cul | Cubloc Studio PLC Information |
| cul | IconForge Cursor Library |
| cul | Petrosys Culture Data |
| cul | Windows Cursor Library |
| cup | Naviter SeeYou Waypoint Data |
| cur | Oasys T/HIS Curve File |
| current | WhatsApp Messenger Encrypted Database |
| cursorfx | CursorFX Theme |
