The startup time increases or hangs at the logon “Welcome” screen if you frequently backup Hyper-V virtual machines on a Windows Server 2008 R2 system

Symptoms

On a computer that is running Windows Server 2008 R2 and that has the Hyper-V role installed, the startup time of the computer keeps increasing. After a while, the computer stops responding when the computer is in the startup process.

Note If the computer runs some virtual machines, this issue usually occurs when you frequently back up all the disks on the computer.

Additionally, many of the following PlugPlayManager events that have Event ID 12 are logged in the System log:

Notes

• The size of the %SystemRoot%\system32\config\system system registry hive increases after every backup operation..

• If you view the registry hive by using Registry Editor, the following registry entries are logged repeatedly. For example, the following registry entries are logged repeatedly 10000 times or more.
  

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\SCSI\Disk&Ven_Msft&Prod_Virtual_Disk

  
  

  HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\STORAGE\Volume\{f1030a29-1024-11df-b7a9-001b214f4bef}#0000000006500000

  
  

  HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\DeviceClasses\{53f5630d-b6bf-11d0-94f2-00a0c91efb8b}\##?#STORAGE#VOLUME#{E717314D-23B5-11DF-AA86-001B214F4BEF}#0000000000100000#{53f5630d-b6bf-11d0-94f2-00a0c91efb8b}"DeviceInstance"="STORAGE\\Volume\\{e717314d-23b5-11df-aa86-001b214f4bef}#0000000000100000"

• This issue also occurs in Windows Server 2008. However, no hotfix is available for Windows Server 2008. To work around this issue, see the "Workaround" section.

Cause

This issue occurs because there are a large amount of orphaned registry keys.

The Volume Shadow Copy Service (VSS) snapshots create many registry keys. However, they are not deleted after the VSS snapshot operations are completed.

Resolution

Workaround

Important
Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
To work around this issue in Windows Server 2008 R2 or Windows Server 2008, clean up all orphaned registry key entries. To do this, follow these steps:

1. Download the DevNodeClean tool.

2. Perform one of the following operations:

   • Run the DevNodeClean tool as administrator.

   • At a command prompt, locate to the folder path of the DevNodeClean.exe file, type the following command, and then press ENTER:

     devnodeclean /r
     Note We recommend that you schedule the devnodeclean /r command to run one time every week.

If the DevNodeClean tool does not work, you can delete the registry keys manually or contact Microsoft Support for help.

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

934234 How to remove registry information about devices that will never be used again on a computer that is running Windows Server 2003

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

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