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Windows VSS bug could cause corrupt backup data

Article ID: 210
Last updated: 19 Dec, 2012

Microsoft released the following information regarding a VSS bug that could lead to potential data loss.
Attix5 strongly recommends applying the Microsoft update as soon as possible, as this could affect the working of the Attix5 Pro VSS plug-in.

Article ID: 2748349 (Full article here)

Corrupted files are found in backup data that is restored by using the Windows Volume Shadow Copy feature in Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, or Windows Server 2008 R2

Symptoms

Consider the following scenario:

  • You create or extend a volume on a computer that is running Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, or Windows Server 2008 R2.
  • The size of the volume that you extend is a multiple of 8 gigabytes (GB). For example, the size of the volume is 8,192 megabytes (MB), or 16,384 MB, or 32,768 MB.
    Note: 1 GB equals 1024 MB.
  • You use a backup application that uses the Windows Volume Shadow Copy feature to create snapshots during a backup process.
  • In this scenario, one or more files are corrupted after you restore the backup data.

Note: NTBackup, Windows Server Backup, System Center Data Protection Manager (DPM) or any third-party backup application’s backup data can be affected. Please contact your third-party backup solution manufacturer to determine whether they use the Windows Volume Shadow Copy feature to create backups.

Cause

This issue occurs because a volume bitmap does not accurately reflect the clusters that are used by the files on a volume that is a multiple of 8 GB. Additionally, this occurs when a Windows Volume Shadow copy is invoked on an extended volume. Therefore, the data that is read or copied from a shadow copy may not accurately represent the file data. When the data is saved to the destination, it is saved in a corrupted state.

Resolution

Please follow the relevant steps as outlined in Article ID: 2748349

Article ID: 210
Last updated: 19 Dec, 2012
Revision: 2
Views: 4347
Comments: 0
Posted: 18 Dec, 2012 by Van Rensburg J.
Updated: 19 Dec, 2012 by Van Rensburg J.
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