Standard procedure is to repeat the Move Data on the possibly bad tape such 
that the next attempt will use a different tape drive, which may be able to get 
a few more entries off the tape. Repeat further within reasonable bounds. 
Thereafter you can perform a Restore Volume (assuming you have a Copy Pool for 
this storage pool) to recover the rest.

You can then invoke whatever tape validation utilities you have to assess the 
quality of the tape, as to whether it should be replaced. (“Tape is tape.”)

   Richard Sims