Media miscompare error for format or erase later

Arcserve Backup indicates "Media MisCompare" Error for Format or Erase.

The media read does not match the media shown by Arcserve Backup. Arcserve Backup does not erase or format media unless it matches what is shown. This error occurs when media is changed manually and not inventoried to update Arcserve Backup. When media is manually added, removed, or moved, the user must inventory the slots or mount the library magazine to update Arcserve Backup.