Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have several errors in my log. My environment is:

  • Server 2008 R2 (virtual machines on Server Core stack).
  • AppAssure Replay 4 as the backup solution.
  • In the evening backup goes okay usually, snapshots get created fine.
  • During the day and other times, it's a different story: Snapshots fail: numerous writers get into a failed state, a timeout.
  • AppAssure's response at one point in time was to restart the Agent service. That solved the problem for a short time, but when I tried it today, that didn't work at all.

I've tried to look high and low for a way to just reset the writers - I thought they were controlled by the VSS Service/Microsoft Shadow Copy Provider, but apparently not. Should I have the Hyper-V Shadow Copy Provider running, over the Microsoft Shadow Copy Provider?

My errors, explicitly:

  • Unable to take VSS snapshot and transfer data for 'C: ...'Error taking VSS Snapshot of volume(s): AsyncWait for DoSnapShotSet failed - Snapshot vetoed by provider.

  • Event ID: 12289, VSS. 'Volume Shadow Copy Service error: unexpected DeviceIOControl (\?\Volume{guid} hr=9x80070057, The parameter is incorrect. Operation: Automatically choosing a different volume. Professing EndPrepareSnapshots Context: Execution, System Provider

  • Event ID: 22, volsnap: The shadow copy storage volume specified for shadow copies on volume C: could not be added.

  • A generic error when I try to view the 'Shadow Copies' tab on my C: drive.

  • Running 'DiskShadow list writers status' gives me the status code 7, and what it means specifically: 'VSS_WS_FAILED_AT_PREPARE_BACKUP'.

I believe, obviously that all these errors are related. Most solutions I see say to stop the VSS and related services, unregister some modules, and register them again as a way of resetting the writers (for Server 2003). I disagree with this solution, there is no reason why I shouldn't be able to solve this without needing to reboot the box; especially in Server 2008.

Any and all help would be greatly appreciated, or at the very least letting me know that I'm perhaps overloading I/O, and to space out my snapshots (they are taken every hour on this server with errors: it's a file-server)

share|improve this question
I had a similar problem. Check out this app I don't remember where it was I think in the support page there was an entire list of ways to fix VSS errors. I ended up re-registering dlls. I don't think a reboot was needed – user122567 May 27 '12 at 16:32
I ended up fixing this issue by moving my backups to a different server with less I/O. It's not perfect, but at least I get much more consistent backups. – DarkSim905 Jun 27 '12 at 16:18

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.