Backup Assist is a wonder data backup and recovery tool, but nothing is perfect and everything has problems here or there. One that I have come across more than once is:
Backup Assist Fails to delete old backup that is not even there any longer. Basically this is due to a corrupted catalog, so we need to rebuild it:
1. Shutdown Backup Assist Service
2. Open explorer and browse to: c:\ProgramData\BackupAssist 6\Catalogues
3. Rename to catalouges.old.
4. Start Backup Assist Service
For any restores using the Restore Console, make sure to point to this .old folder if restoring from a date in that .old timeframe. If Single Instance Store can just drag and drop from the backup drive.