Mikael,
            The VCR data is written after every write to the tape. If you
have had errors during backup on the drive then this data may be corrupted
as it may not have been updated after the last write. I believe that this
will be
corrected the next time the tape is written to successfully. If you are
using 3590's it mentions this in one of the manuals (I forget which one)

Nick Clayton
(Vertex Data Science)