Two things Re despooling-
1) You can recover the tape if it despools
Carefully undue the screws on the back open the case and wind the tape back onto the other spool .
You will have to wind it on until you see two little holes in the tape near the metal side.
I think this was caused by a bad sector on my hard disk resulting in a file with no endoffile.
I have repaired 5 like this. I then used a second, reliable machine to format them.
2) Is there a way to reset the Tape drive. It still can't seem to find the end of tape marker. It is an ADR2.60 USB. I took it out of the case and mounted it as ide to Flash it as 5.05 and the flash said it was OK but if left ot it's own devices, it will happily despool a tape. Could this be a hardware problem ?