This article was previously published under Q234492
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If you share Windows 2000 Backup (NTbackup.exe) tapes between two or more computers, select the Replace the data on the media with this backup option during a backup operation, and enter a new media label name, Backup creates and writes a new Globally Unique Identifier (GUID) on the tape.
If you move the tape back to a computer that has already inventoried the tape, Removable Storage Manager (RSM) moves the media into the Import media pool rather than back to the Backup media pool where it originated. This occurs because the tape's new GUID does not match any found in the RSM local database, and RSM considers it to be a foreign tape.
This also causes any statistics kept for this tape to be lost on the original computer because the tape is considered a new imported tape.
NOTE: The original tape is still listed in the Off-Line media library. Because that tape can never be remounted (because the GUID is no longer valid), it can be safely deallocated and then deleted from Removable Storage Manager (RSM). If media statistics are important, view and record them before deleting the tape.
RSM and Backup have no reliable way of tracking media label changes when you are sharing media between computers. To ensure that media can be mounted and used reliably between computers, a new GUID is written to the tape when the media label name is changed.
If you want to maintain accurate media usage statistics and ensure that backup media is placed back into the Backup media pool and not left in the Off-Line media pool, do not change media label names when you overwrite data on tapes shared between computers.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
Some tape devices do not move media to the Off-Line media library when a tape is ejected. Consequently, if the tape changer device is set to perform only a "fast" inventory, the device may believe that the reintroduced tape is still the original tape with the same GUID. This prevents you from using the new media or deleting the old media until the tape is mounted and reinventoried.
For additional information, please click the article number below to view the article in the Microsoft Knowledge Base:
234579 RSM Eject Command May Not Move Media to Off-Line Media Library