After replacing tapes in the library the following message is found in the device logs:
"Lost move destination from internal tree"
This happens during various tape operations such as moving, loading, unloading, scanning, modifying media.
Using the following scenario:
Dell Tape Library with 2 Drives and 20 Slots.
All 20 slots have tapes in them. Both drives have tapes in them as well.
One tape must be ejected either from the drive, or from the slot to allow for media movement.
All 20 slots have tapes in them. At least 1 drive is empty.
This is acceptable because there is an available drive to load/unload the media into.
A media request ALWAYS loads tapes into the drives, and with one available, this means there is always room to move media around.