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

Article:TECH64487  |  Created: 2010-02-08  |  Updated: 2011-08-13  |  Article URL
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Technical Solution



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


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


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
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
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.
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)
Figure 2.


 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

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]"

Windows Server 2008 Hyper-V VSS writer is not used during a backup job because of corrupted or invalid virtual machine configuration files

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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