| 251. | .cra | Advanced crack file (usually text) |
| 252. | .crc | Check file (Win-SFV32) (Fantasia Software) ◊ Circular reference file (Pro/Engineer) |
| 253. | .crd | Cardfile (Windows 3.x - YourWay) |
| 254. | .crf | Bitmap graphics (Calcomp Raster File) (black and white or 4bit CMYK) ◊ Cross-reference (MASM - Zortech C++) |
| 255. | .crh | Image file (Microsoft Golf) |
| 256. | .crk | Crack file (usually text) |
| 257. | .crp | Custom Report file (Visual dBASE) ◊ Encrypted database (dBASE IV) ◊ Run-time presentation (Corel Presents) |
| 258. | .crs | Cursor image ◊ File Conversion Resource (WordPerfect 5.1) |
| 259. | .crt | Crontab file ◊ Internet security certificate ◊ Terminal settings information (Oracle) |
| 260. | .cru | Compressed file archive (CRUSH) |