Error Message "The Backup File Is Unusable" When You Try to Restore Backup File (269826)


The information in this article applies to:

  • Microsoft Windows 2000 Server SP1
  • Microsoft Windows 2000 Advanced Server SP1
  • Microsoft Windows 2000 Professional SP1
  • Microsoft Windows 2000 Datacenter Server
This article was previously published under Q269826

SYMPTOMS

When you try to add data to or try to restore data from a Microsoft Windows 2000 backup (.bkf) file, you may receive the following error message:
[Unrecognized Media]
The backup file is unusable. You must erase it, or choose another file.
When you receive this error message, your only option is to click OK in the dialog box.

CAUSE

The backup file is corrupted, and it is not in a valid Windows 2000 backup file format. When Windows 2000 opens a backup file, it checks the file to make sure that it is a valid backup file. If the file is incomplete or corrupted, the backup file process cannot add or restore any data to or from the file.

RESOLUTION

When a backup file is corrupted, it can no longer be used by the Windows 2000 backup process. To make sure that the integrity of a backup file is maintained, select the Verify Data After Backup advanced option when you perform any backups. This option makes sure that your computer system's backup process completes successfully and maintains the integrity of the backup files. To make sure that the backup process completed without errors, also check the backup report.

The backup process posts two event messages in the Application Event log for each backup operation, followed by two more event messages for the verify operation process. To make sure that each backup task begins and ends successfully, check to see that your computer displays the following messages: 

Event Type:	Information
Event Source:	NTBackup
Event Category:	None
Event ID:	8000
Computer:        COMPUTER_NAME
Description:
Begin Backup of 'System State'     Verify:  On         Mode:  Append         Type:  Copy 

Event Type:	Information
Event Source:	NTBackup
Event Category:	None
Event ID:	8001
User:		N/A
Computer:        COMPUTER_NAME
Description:
End Backup of 'System State'     Verify:  On         Mode:  Append       Type:  Copy

Event Type:	Information
Event Source:	NTBackup
Event Category:	None
Event ID:	8008
User:		N/A
Computer:        COMPUTER_NAME
Description:
Begin Verify to 'System State' 

Event Type:	Information
Event Source:	NTBackup
Event Category:	None
Event ID:	8009
User:		N/A
Computer:        COMPUTER_NAME
Description:
End Verify to 'System State'

Note Partitions that are formatted by using the FAT and FAT32 file system have a maximum file size limit of 4 GB or 4,294,967,296 bytes (2^32 sectors). When you try to back up your files to a FAT or FAT32 volume and the backup data exceeds the maximum file size that is permitted, the backup process may report the following error message:
[Insert media]
The fixed media is full. You cannot back up all of the specified data to this disk device.
The backup operation will stop.
In some circumstances, this process may lead to a corrupted backup file. The NTFS file system has a theoretical maximum file size of 16 exabytes (2^64 sectors).

To make sure that no errors are reported, review your backup reports and Application Event logs after you perform unattended backups.
Modification Type:MinorLast Reviewed:1/26/2006
Keywords:kberrmsg kbprb KB269826
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