2008 R2 Hyper-V WBadmin failure

Situation:

2008R2 Hyper-V Host.

C: is system only. 

D: is hyper-v system files and VM VHD’s

Doing a complete server scheduled Windows Backup fails:  "The backup operation that started at '‎2010‎-‎02‎-‎13T06:21:44.876000000Z' has failed because the Volume Shadow Copy Service operation to create a shadow copy of the volumes being backed up failed with following error code '2155348001'. Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.

Drive C: backed up from command line just fine:

wbadmin start backup -backuptarget:\\network\share -include:c: -allcritical -quiet

Drive D: (288 GB of VM VHD) fails even from command line.

Solution:

Read this and then do the following.

Open an elevated command prompt and do “vssadmin list writers”

In my case this is the result (and it matches the reference CSS advice). Remember that the CSS advice is to double-check this value as yours MAY be different.

Writer name: 'Microsoft Hyper-V VSS Writer'
   Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
   Writer Instance Id: {7df567b8-ed9f-4383-ae86-0489c9569cc2}
   State: [5] Waiting for completion
   Last error: Unexpected error

goto: 

1. hklm\software\microsoft\windowsNT\currentversion\spp
2. Add a new key as type reg_Multi_SZ
3. Name for new key: DisabledWriters
4. Value for new key: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de} (remember that yours may be different - run a vssadmin list writers to determine your value for the key)
5. net stop wbengine
6. net start wbengine

My windows backup immediately worked properly, backing up over 280GB of active VM VHD’s.