tape_34xx.3f2d36 <bus ID of the tape device>: The tape unit does not support format 3480 XF
Explanation
The tape unit does not support tapes recorded in the 3480 XF format.
User response
If you do not need the data recorded on the current tape, rewind the tape
and overwrite it with a supported format. If you need the data on the
current tape, use a tape unit that supports the tape format.