Moving Cartridges Before Removing Cells from a Partition
The SL4000 can partition down to the drive and cell level. If cells are reassigned from one partition to a different partition, cartridges in those cells will be orphaned, and they will no longer be accessible by the partition that they were in before.
To avoid this, before re-partitioning an SL4000, move cartridges to cells that will remain in your partition.