Every few months, my weekly Filefort incremental backup fails with the message that "the USB stick or external drive is not the original drive where the backup resides". This is simply not true - there is an external drive, always connected, with all the backups in place. I then have to start afresh, whereupon it creates a new complete backup, overwriting the original. I could create a new job every time this happens (to avoid the overwrite), but until I see the error message, the backups are simply failing for no good reason. Any thoughts?