Phantom Drive

We recently experienced an issue with a drive that we could not remove or force delete. What was happening is that TSM continually tried to dismount a volume from this drive but failed. The tape it was trying to dismount was in its home slot and not in the drive and the drive showed idle in ACSLS. TSM would not let us remove the path for it so we could not eliminate the problem. We tried a reboot and the dismount retries came up with the TSM server and NOTHING could get rid of the issue. Even turning the drive off in the library did not eliminate the "phantom" dismount attempt by TSM (We even removed the device from AIX to no avail). So did my manager finally find to be the issue? It turned out to be an incorrect WWN for the drive. How it got changed we have no idea...but it did and it caused days worth of headaches and flooded the activity log with errors. So it you ever come across a "phantom" drive check the WWN and make sure you don't suffer as we did.