Data Protector keeps a record of tape usage and after some time marks tapes as “POOR”, making them unusable for backups.
But that doesn’t mean that the tape is really poor.
To make the tapes usable again just open a command line or a Unix terminal and place yourself in the OmniBack/bin directory.
Then just type omnimm -reset_poor_medium tapelabel. Then you will receive the message “Reset poor flag on medium.”
Please note that running this command will reset the medium counters, including number of overwrites, creation time, last write/overwrite/access times. Use omnimm -media_info tapelabel -detail to confirm there are no errors or you will end up with a “GOOD” tape with errors.