Virtual Machines not visible under "Microsoft Hyper-V' in Backup Selections List.

Problem

Virtual Machines not visible under "Microsoft Hyper-V' in Backup Selections List.

Error Message

An attempt to browse the Microsoft Hyper-V Agent in backup selections doesn't show any Virtual Machines (VM) listed.(FIGURE 1)
(FIGURE 1)
 

Cause

This is because of the unavailability of Microsoft Hyper-V VSS Writer when the command "Vssadmin List Writers " is executed on Windows 2008 Server with Hyper-V installed or due to corrupted or invalid virtual machine configuration files.
 
In addition, the following events are recorded in the Application Event Log.
*******************
Source: VSS
Event ID: 12301
Description:
Volume Shadow Copy Service error: Writer Microsoft Hyper-V VSS Writer did not respond to a GatherWriterStatus call.
*******************
Log Name: Application
Source: VSS
Event ID: 12366
Description:
An unhandled exception was encountered while processing a VSS writer event callback. The VSS writer infrastructure is in an unstable state. The writer hosting process must be restarted in order to resume VSS functionality.
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In order to confirm this issue,open the "Server Manager" > "Roles" (Start > Programs > Administrative tools > Server Manager). Highlight the "Hyper-V" role on the right hand side to see a "Summary" which will ideally capture all the events for "Hyper-V".In the Summary section, Multiple Event ID 10107 and the source as "Hyper-V VMMS" (Hyper-V Virtual Machine Management Service) are recorded.The description provided is as follows:
***********************
An error occurred while identifying the Hyper-V VSS writer. Check for any corrupt or invalid configuration files and try again. (Figure 2)
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Figure 2.
 
 
 
 
 

Solution

 1) Install the following  Windows 2008 (64 bit) Hotfix(s) downloadable from Microsoft:

An update is available for Windows Server 2008-based computers to address issues with backing up and restoring Hyper-V virtual machines
 http://support.microsoft.com/kb/959962

Error message when you back up a Windows Server 2003-based virtual machine on a Windows Server 2008 Hyper-V-based computer: "GetWriterStatus FAILED for Selected writer [Microsoft Hyper-V VSS Writer], writer is in state [9] [VSS_WS_FAILED_AT_FREEZE]"
 http://support.microsoft.com/kb/959978

Windows Server 2008 Hyper-V VSS writer is not used during a backup job because of corrupted or invalid virtual machine configuration files
 http://support.microsoft.com/kb/956697

2) Reboot the Windows 2008 Hyper-V Server.

NOTE:  If the Hyper-V VSS writer continues to disappear from the Windows 2008 Hyper-V host restart the "Hyper-V Management Service" to reregister the Hyper-V writer without rebooting the host machine. See related documents for additional Microsoft Patches that can help resolve the issue.

If the Microsoft Hyper-V VSS writer is not available or disappears from the host even after following the above steps,contact Microsoft Technical Support for further assistance with Hyper-V.
 
 
 

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