Backup files that are created by using the Windows Volume Shadow Copy feature are corrupted in Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, or Windows Server 2008 R2

Symptoms

Assume that you have a computer that is running Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, or Windows Server 2008 R2. You use a backup application that uses the Windows Volume Shadow Copy feature to create snapshots and read files from the snapshots. In this situation, one or more corrupted files are found in the snapshots.

Notes

• The corrupted files can be backed up by using the backup application. The corrupted files can only be noticed during a restore process.

• The backup data of any third-party back up application can be affected. For example, NTBackup, Windows Server Backup, System Center Data Protection Manager (DPM) 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 some regions in the snapshot are not protected when the original volume is changed. When the file is read from the snapshot, the file data is not consistent. Therefore, the file data becomes corrupted. When a backup is taken by using this snapshot, the corrupted file is stored later.  

Free clusters in a volume comply by using the following pattern:

Note White regions in the pattern represent free clusters.



The Windows Volume Shadow Copy feature cannot protect the second region that is being used. Therefore, when blocks are read by an application, the old content is overwritten by the new content.

This pattern occurs when the current size of the volume that you extend is a multiple of 8 gigabytes (GB) by a size that is larger than 8 GB. The chances to obtain the pattern are increased in the following conditions:

• The initial size of the volume that you extend is a multiple of 8 GB.

• The volume is frequently extended by multiple of 8 GB.

Note The pattern occurs in other situations too. The previous cases of corruption increase the occurrence of the pattern.

Resolution

Windows Vista and Windows Server 2008 file information notesImportant Windows Vista updates and Windows Server 2008 updates are included in the same packages. However, only "Windows Vista" is listed on the Update Request page. To request the update package that applies to one or both operating systems, select the update that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each update applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.

  Version	Product	SR_Level	Service branch
  6.0.600 2. 22xxx	Windows Vista and Windows Server 2008	SP2	LDR

Windows 7 and Windows Server 2008 R2 file information notes
Important Windows 7 updates and Windows Server 2008 R2 updates are included in the same packages. However, updates on the Update Request page are listed under both operating systems. To request the update package that applies to one or both operating systems, select the update that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each update applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

  Version	Product	Milestone	Service branch
  6.1.760 0.17xxx	Windows 7 and Windows Server 2008 R2	RTM	GDR
  6.1.760 0.21xxx	Windows 7 and Windows Server 2008 R2	RTM	LDR

• GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain updates in addition to widely released fixes.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about this issue, click the following article number to view the article in the Microsoft Knowledge Base:

976329 Error message when you run the ChkDsk.exe utility in read-only mode on a Windows-based computer: "The Volume Bitmap is incorrect" or "Error detected in index $I30 for file 5" For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684Description of the standard terminology that is used to describe Microsoft software updates

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.