| bk | Movie Magic Screenwriter Document Backup |
| bk | Power Chess Book Data |
| bk0 | Aspen HYSYS Backup File |
| bk1 | Aspen HYSYS Backup File |
| bk1 | CA ERwin Data Modeler Backup |
| bk1 | FlashGet Database Backup |
| bk1 | Windows Indexing Service Data |
| bk2 | Aspen HYSYS Backup File |
| bk2 | Cashbook Complete Automated Backup Data |
| bk2 | FlashGet Database Backup |
| bk2 | Windows Indexing Service Data |
| bk3 | Cashbook Complete Automated Backup Data |
| bk3 | Cashbook Complete Company Data |
| bk3 | FlashGet Database Backup |
| bk4 | FlashGet Database Backup |
| bka | Oracle Enterprise Manager OMS Backup Data |
| bkb | VariCAD Block File |
| bke | BackupEarth Compressed Data |
| bkj | Symantec Backup Exec Job |
| bkl | KeyCarbon Binary Keystroke Log |
| bkmk | Internet Explorer Bookmark Data |
| bkmk | Yummy FTP Pro Bookmark |
| bkp | Steinberg WaveLab Backup Plan |
| bkr | BK ReplaceEm Fileset |
| bksln | Freescale BeeKit Solution File |
| bkt | Zortech 3 Tools Samples Data |
| bku | Sage Timeslips Backup |
| bkup | Groundspeak Wherigo Backup File |
| bkx | X-Rite eXact Manager Device Backup |
| bky | bookkey Bookmark Data |
