Hello,
thanks for the reply.
The backup is to external Tape. Since it is a single tape system, we created a media set (daily) whose properties are "overwrite protection: NONE" and "append period: 0 hours". A second media set (used) has similar properties and tapes are logically placed in this set after each use. The job is configured to use tapes from the first media set only. Each day the job is checked, the media is removed physically from the device and logically from the media set. The next days tape is placed in the device and then logically moved from the "used" media set to the "daily" set.
This works well 99+% of the time. Rarely we have the situation as described. When the job is checked it has run successfully, however the media set (daily) now shows 2 tapes (one black and one blue) The blue tape label is defaulted to 8MM000001, 2,3 etc.