Microsoft KB Archive/926185
Article ID: 926185
Article Last Modified on 10/23/2007
- Windows Vista Business
- Windows Vista Enterprise
- Windows Vista Home Basic
- Windows Vista Home Premium
- Windows Vista Ultimate
- Windows Vista Enterprise 64-bit Edition
- Microsoft Windows Code Name “Longhorn”
This article discusses a beta release of a Microsoft product. The information in this article is provided as-is and is subject to change without notice.
No formal product support is available from Microsoft for this beta product. For information about how to obtain support for a beta release, see the documentation that is included with the beta product files, or check the Web location where you downloaded the release.
When you use the System Restore feature in Windows Vista, you receive the following message:
Additionally, only the most recent backup files from Windows Vista Complete PC Backup are available. Earlier versions of the backup files are unavailable. You experience this problem if you are running Windows Vista or Windows Server 2008 on a computer that is also configured to run an earlier Windows operating system.
Note This configuration is known as a dual-boot configuration.
This problem occurs when you start the computer by using the earlier operating system, such as Microsoft Windows XP or Microsoft Windows Server 2003. In this situation, the earlier operating system deletes all the restore points that were created in Windows Vista. The earlier operating system also deletes all Complete PC Backup files except the most recent version of these backup files.
You can use either of the following methods to work around this problem.
To keep Windows XP from deleting restore points of the volume in Windows Vista, add the following registry entry under the
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices\Offline registry subkey in Windows XP:
Value name: \DosDevices\D:
Value data: 1
Note If the
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices\Offline registry subkey does not exist, you must manually create this registry subkey. Create this registry entry when you have installed Windows Vista on the "D" partition in Windows XP.
Effects of this workaround
After you restart Windows XP, you cannot access the volume that is created in Windows Vista from Windows XP. However, you can still access the volume that is created in Windows XP from Windows Vista. You must use Windows XP drive or an additional drive such as a USB thumb drive for data exchange.
Limitations of this workaround
This workaround only protects the volume in Windows Vista from being accessed or changed by Windows XP. If you have more volumes or if you want to add a volume from Windows XP to the system restore settings in Windows Vista, the system restore (Volume-Shadow-Data) on those volumes will be still overwritten. To avoid this problem, you must add those volumes to the
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices\Offline subkey. If you add the Windows XP volume to that subkey or if you delete this volume drive letter, you cannot then start Windows XP.
You can use this workaround only when the restore points for Windows XP and for Windows Vista are mutually exclusive. The restore points are mutual exclusive when no restore points are common across the volume in Windows XP or the volume in Windows Vista. For example, consider the following scenario:
- The C driver is a volume in Windows XP.
- The D driver is a volume in Windows Vista.
In this scenario, the Windows Vista restore points are added on the E driver. Then, you must change the registry entry of the E driver under the
HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices\Offline" registry subkey to 1.
Also, a common volume can be used for data exchange between Windows XP and Windows Vista. However, restore points must not be defined on this common volume.
Support Status of this workaround
Adding this key can have unwanted side-effects to your installation. For example, applications that put data on this drive before available may fail. If there is a reporting problem reported to Microsoft, you will be asked to delete this value
To work around this problem, use the Bitlocker feature on the volume in Windows Vista.
Bitlocker is a built-in security feature in Windows Vista. When Windows Vista starts, the Bitlocker feature should be enabled on the Windows Vista volume on which Windows Vista restore points are enabled. When Windows XP or Windows Server 2003 starts, the Windows Vista volume on which the Bitlocker feature is enabled is inaccessible. Therefore, the Windows Vista restore points are intact.
This workaround works for dual-boot configurations (Windows XP or Windows Server 2003 together with Windows Vista).This workaround requires no changes to Windows XP. Therefore, the volume in Windows Vista is still inaccessible when the system is started in Windows XP or in Windows Server 2003.
Note The Bitlocker feature is available for Windows Vista Enterprise Editions and for Windows Vista Ultimate Editions.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about how to configure a dual-boot environment in Windows Vista, visit the following Microsoft Web site:
Information for advanced users
Consider the following scenario. A shadow copy is created on a volume in Windows Vista or in Windows Server "Longhorn." Then, you access the volume from an earlier Windows operating system. In this scenario, the shadow copy is deleted. You experience this problem if one or more of the following conditions are true:
- You use Windows Vista or Windows Server 2008 in a dual-boot configuration with Windows XP or with Windows Server 2003. In this scenario, any restore points that have been created in Windows Vista are lost when the computer is started in an earlier Windows operating system. Additionally, shadow copies that were created in Windows Server 2003 are lost when the computer is started in Windows Vista or in Windows Server "Longhorn."
- You create Windows Vista restore points on an internal hard disk or an external hard disk. Then, you move the hard disk to a computer that is running Windows Server 2003 or Windows XP.
- You use an internal hard disk or an external hard disk to store Complete PC Backup files, and you then access the volume from either Windows Server 2003 or Windows XP. In this scenario, all earlier versions of the backup files are lost. Only the most recent backup files are still available.
This problem occurs because the volume snapshot driver that is included with Windows Vista and with Windows Server 2008 uses disk structures that are incompatible with earlier versions of Windows. Therefore, the earlier operating system deletes Windows Vista shadow copies or Windows Server 2008 shadow copies together with the associated restore points. This behavior occurs because the earlier Windows operating systems do not recognize the new disk structures.
- In Windows Vista, shadow copies are used to maintain restore points. Additionally, shadow copies are used to maintain Complete PC Backup files. Therefore, when you access the volume from an earlier operating system, the restore points or the earlier versions of Complete PC Backup files are lost.
- Although Windows Server 2008 does not include the System Restore feature, Windows Vista and Windows Server 2008 use shadow copies for other purposes, such as for backups. Windows Vista and Windows Server 2008 also delete shadow copies that are created by earlier versions of Windows. Therefore, after you use the earlier version of Windows to start the computer in a dual-boot environment, no restore points are available to the System Restore feature when you next start Windows Vista.
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