A Windows Server 2008-based computer that is connected to a storage device over MPIO paths does not restart if the storage device is a boot device, or you lose access to the device if the device is a data volume

Consider the following scenario:

• You are running a Windows Server 2008-based computer that is connected to a storage device over some Microsoft Multipath I/O (MPIO) paths.
• A Microsoft MPIO Device Specific Module is enabled for these MPIO paths.
• The storage device is configured as an iSCSI boot device or a Storage Area Network (SAN) boot device.
• You install and then uninstall Windows Server 2008 Service Pack 2.
• You have installed hotfix 957316 on the Windows Server 2008-based computer.

In this scenario, the computer does not restart if the storage device is a boot device, or you lose access to the device if the device is a data volume.

Note For more information about hotfix 957316, click the following article number to view the article in the Microsoft Knowledge Base:

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
To avoid this problem, install hotfix 967752 before you install Windows Server 2008 Service Pack 2.

Scenario 1

If you have installed Windows Server 2008 Service Pack 2 and then you uninstalled the service pack or if you have not installed Windows Server 2008 Service Pack 2, follow these steps:

• For the Data Volume
  1. Click Start, click Run, type regedit, and then click OK.
  2. In Registry Editor, locate the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEV
  3. Copy the entries under the MPDEV subkey, and then enter them under the following subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList
  4. Restart the computer, or disable and then enable host bus adapter (HBA).
• For the Boot Volume
  1. Mask logical unit number (LUN) to another Windows Server 2008-based computer, and then mount the boot volume.
  2. Locate the registry (.reg) files.
  3. Click Start, click Run, type regedit, and then click OK.
  4. In Registry Editor, locate the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEV
  5. Copy and paste the registry data in the registry subkey of step 4 under the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList
  6. Unmount the boot volume, and then unmask the LUN from the Windows Server 2008-based computer.
  7. Mask the LUN to the Windows Server 2008-based computer for SAN Boot.
  8. Restart the computer, and then boot from this LUN.

Scenario 2

If you experience this problem when you prepare for the installation or removal of Windows Server 2008 Service Pack 2, follow these steps:

• For the Data Volume
  1. Click Start, click Run, type regedit, and then click OK.
  2. In Registry Editor, locate the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEV
  3. Copy and paste the registry data in the registry subkey of step 2 into the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList
  4. Restart the computer, or disable and then enable the host bus adapter (HBA).
• For the Boot Volume
  1. Mask logical unit number (LUN) to another Windows Server 2008-based computer and then mount the boot volume.
  2. Locate the registry (.reg) files.
  3. Click Start, click Run, type regedit, and then click OK.
  4. In Registry Editor, locate the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MPDEV
  5. Copy and paste the registry data in the registry subkey of step 4 into the following registry subkey:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList
  6. Unmount the boot volume, and then unmask the LUN from the Windows Server 2008-based computer.
  7. Mask the LUN to the Windows Server 2008-based computer for SAN Boot.
  8. Restart the computer, boot from this LUN.
     
     Note When you install Windows Server 2008 SP2, the
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msdsm\Parameters\DsmSupportedDeviceList
     registry subkey is backed up to the following file:
     %windir%\system32\DsmSupportedDeviceList.txt

Update information

The following files are available for download from the Microsoft Download Center:

Download the Update for Windows Server 2008 (KB967752) package now.

Download the Update for Windows Server 2008 for Itanium-based Systems (KB967752) package now.

Download the Update for Windows Server 2008 x64 Edition (KB967752) package now.

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

Hotfix information

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

• The files that apply to a specific product, milestone (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
  6.0.6000.16xxx	Windows Vista	RTM	GDR
  6.0.6000.20xxx	Windows Vista	RTM	LDR
  6.0.6001.18xxx	Windows Vista SP1 and Windows Server 2008 SP1	SP1	GDR
  6.0.6001.22xxx	Windows Vista SP1 and Windows Server 2008 SP1	SP1	LDR

• Service Pack 1 is integrated into Windows Server 2008.
• The .manifest files and the .mum files that are installed in each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. These files and their associated .cat (security catalog) files are critical to maintaining the state of the updated component. The .cat files are signed with a Microsoft digital signature. The attributes of these security files are not listed.

For all supported x86-based versions of Windows Server 2008

For all supported x64-based versions of Windows Server 2008

For all supported Itanium-based versions of Windows Server 2008

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Server 2008

Additional files for all supported x86-based versions of Windows Server 2008

Additional files for all supported x64-based versions of Windows Server 2008

Additional files for all supported Itanium-based versions of Windows Server 2008