I have a server running Windows Server 2012 Core Hyper-V. This server currently hosts two virtual machines (one Windows Server 2008 and one Windows Web Server 2008). Occasionally, without any warning, I am unable to access any of the VM’s. By using Hyper-V Manager to connect to the host, I can see that they got an Off-Critical state.

If I try to start them, I get a "An attempt to read or update virtual machine configuration failed." error message. I'm only able to start the VM’s by restarting the host itself.

By looking at the logs on both of the VM’s, I don’t see anything that might help me figure out what is going on:

  • The last event logged, before going down, is an Info about the uptime (“The system uptime is 70378 seconds.”),

  • ...followed by another one stating that the OS has started, an Error saying that the previous shutdown was unexpected and a Critical saying “The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.”.

Looking at the host's logs doesn't help much either. I don't see any error messages around the time the VM's got shut down suddenly:

  • Just two Info's about Windows Update service starting and stopping (unrelated as they happen 2-3 hours before the VMs' crashes)

  • ...followed by a (more suspicious) Warning "Reset to device, \Device\RaidPort1, was issued." (@ some seconds after the VMs crashed) and a whole bunch of "The IO operation at logical block address 0x... for Disk 1 was retried." ones. Perhaps this could be related?

Any ideas on what might be causing my VM's to crash? Suggestions on actions to be taken? Thanks in advance.


The only time I have seen this happening is with underlying storage issues either dodgy SSD, or running out of space. if that's not it please give us somne more info

  • This should probably be a comment until conclusive :) – Will Jan 4 '16 at 12:23
  • This might be the cause. I'm testing it and will mark the answer as accepted as soon as I'm sure. – user1987392 Jan 8 '16 at 8:56
  • Looks like there are indeed issues one of the hard drives (problem doesn't occur if I unplug it). Gotta replace it. – user1987392 Jan 14 '16 at 9:57

Check your disk and storage sub-system health. Also make sure that antivirus is configured as required for Hyper-V: http://social.technet.microsoft.com/wiki/contents/articles/2179.hyper-v-anti-virus-exclusions-for-hyper-v-hosts.aspx

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