KB article 958662 explains how to user Windows Server Backup, the new backup software included with Windows Server 2008 and Windows Server 2008 R2, to backup up Hyper-V virtual machines. The article walks you through creating a new Registry value to enable support for the Volume Shadow Copy Service (VSS) provider for Hyper-V. I have put together a command line that does it for you, just copy, paste and run it on your server.
reg add “HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWindowsServerBackupApplication Support{66841CD4-6DED-4F4B-8F17-FD23F8DDC3DE}” /v “Application Identifier” /d Hyper-V /t REG_SZ
To verify that the key was created successfully you can use vssadmin.exe:
vssadmin.exe list writers
If everything is in order the result will include an entry for the Microsoft Hyper-V VSS Writer:
Writer name: ‘Microsoft Hyper-V VSS Writer’
Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
Writer Instance Id: {f3358397-0e40-4c97-b845-d9ec930740e6}
State: [1] Stable
Last error: No error
Notice the Writer Id for the provider, which is identical to the one created in the Registry.
More info:
The writer are default available for the R2 server i thinkMr.T