Error message when you try to perform a system state backup in Windows Server 2008: "ERROR - The location for backup is a critical volume"

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When you try to perform a system state backup to a volume on which the system state file resides, you receive the following error in Windows Server 2008:

This behavior occurs because system state backups to critical volumes are blocked in Windows Server 2008.

You can change the default behavior of Windows Server 2008 by adding a registry entry. You must also verify that the following prerequisites are met before you perform a system state backup to a critical volume.

Prerequisites to perform system state backups to critical volumes

• Make sure that the target volume has no shadow copy before the backup starts.
• If a system state backup is stored on a source volume, backup settings should be configured for full backups. By default, settings are configured for full backups.
• Periodically check that no other user or program maintains a shadow copy on the target volume.
• Do not keep volume level backups and system state backups in the same location.
• The volume used to store the system state backup needs twice the amount of free space as the size of the system state backup until the backup completes.

Registry entry to enable system state backups to critical volumes

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
To enable the system state backup files to be targeted to critical volumes, you must set the value of the AllowSSBToAnyVolume registry entry under the following registry subkey:
Set the value of this entry as follows:Note When this value is set to 1, system state backups to any volume are enabled. To revert to the default behavior, set the value to 0.

The restriction to target the system state backup to any volume is a new feature in Windows Server 2008.

Steps to reproduce the behavior

1. Install Windows Server 2008.
2. Install the Windows Server Backup feature from the Server Manager snap-in.
3. Perform a system state backup by typing the following command at a command prompt:
   wbadmin start systemstatebackup -backuptarget:Drive_Letter:
   Note In this command, Drive_Letter represents a critical volume. Examples of a critical volume include the boot volume and the system volume. Typically, this critical volume is drive C.

For more information about Windows Server 2008, visit the following Microsoft Web site: