Library operations cannot be performed using the drive because a volume is still mounted in it. This may be due to a prior dismount failure that occurred on the drive.
The command fails. The drive may be taken offline.
See previous error messages and the system error logs to determine the cause of the dismount failure or any other reason the volume would still be loaded in the drive. Hardware diagnostics may be required. If necessary, remove the volume manually and place it in its storage cell. If the storage cell is unknown, place the volume in any cell and issue the AUDIT LIBRARY command. Use the QUERY DRIVE command to determine the online status of the drive. If the drive is still functioning, change the status with the UPDATE DRIVE command.