Problem starting Hyper-V VM on CSV cluster node

During the testing of Hyper-V live migration on a freshly built failover cluster (2008 R2), all seemed to work well apart from one Linux (CentOS) VM. It had been running fine on a single Hyper-V server with the integration components installed, however when I tried to do a live migration it failed, not giving much clue why.

Moving the VM to the other node and starting it using the Hyper-V manager, generated the following error…

‘SV04’ failed to start.
Microsoft Emulated IDE controller (Instance GUID): Failed to power on with error ‘a device attached to the system is not functioning’

Failed to open attachment: C:\ClusterStorage\Volume1\Hyper-V\Virtual Hard Disks\SV04.vhd. Error – A device attached to the system is not functioning. (0x8007001F)

After some investigation, I found that the VM would only start on whichever cluster node was the owner of the CSV (Custer Shared Volume). I later discovered that disabling the AV (Sophos in this case) on the node that wasn’t the CSV owner resolved the issue – Odd, as I had added an exclusion for scanning on c:\ClusterStorage\*, seems that the exclusion didn’t quite work with it being CSV due to the way it links into the filesystem… Adding an exclusion for *.vhd, then renabling the AV fixed the issue.


  • Graham commented on March 16, 2011

    You are a champion. Been looking all day for this. Applies to any type of VM (not just Linux)

  • Joyce commented on July 25, 2011

    Thank you for this solution. Worked like a charm :)

  • Jaki commented on July 28, 2011

    Same problem, Worked for me!!! Many thanks!
    “NASA: failure is not an option” :)

  • Vlada commented on November 11, 2011

    Same problem with SOPHOS, you should exclude:

    C:\Users\Public\Documents\Hyper-V\Virtual Hard Disks\

  • Jase commented on November 13, 2011

    Yo man, thanks so much for this, I was shitting brick and MS’s KB is crap too.. thanks for posting it !

  • karbonadas commented on February 10, 2012

    Thanks man alot of, i disabled my NOD and everything working :)

  • Brett commented on March 16, 2012

    Thank you net filled with backup driver issues this is the only post I could find with relative info!

  • Alan commented on July 11, 2012

    Thanks for the info. Respolved a problem we came across today. Have now disabled SOPHOS for the moment. Will be reporting this issue.

  • Tim David commented on September 26, 2012

    I love you! Been trying to resolve this for two days.

  • Ratz commented on May 9, 2013

    Good grief! Thanks! I was going gently spare trying to work out what the issue was. I could tell where the files were, I knew they were there, why can’t you see them damn it?! Well, now I know!

  • Tim David commented on August 22, 2013

    A year later, I end up on this page again with the same problem! Thanks again

  • Paul commented on October 11, 2013

    you are a legend. we just recently cutover to sophos and alas this was the cause.

  • A. Roldan commented on March 23, 2015

    Posts like this make your day! Many thanks for sharing the solution Mr Kendal. It worked for us.

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