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Unable to create snapshots of any VM because of error 0xE03A0015 - any ideas? RRS feed

  • Question

  • On a Server 2008 SP2 host I am suddenly unable to create any snapshots of VMs. Creation initially fails with the event "cannot create the storage required for the snapshot <path to .avhd>" (event 16370) with error detail 0xE03A0015. The path is valid with appropriate permissions, 86GB free and a healthy file system, so I suspect that the cause is something external interfering. What does error code 0xE03A0015 mean?

    After a failed attempt to create a snapshot, the VM settings become damaged so the virtual hard disk  path points to the snapshot .avhd (that wasn't created) instead of the .vhd. Trying to take a second snapshot results in the same event with error detail 0x80070002 (file not found). The Hyper-V-VMMS log will also contain a lot of warnings about missing snapshots (event ID 14250), but other VMs with already existing snapshots still work.
    When I trace the vmms.exe process with Process Monitor, I see that the .avhd file is created and about 1MB written to it before it is closed and immediately deleted. There is no other activity going on at the same time that looks suspicious.

    So, I would appreciate any clues to the initial 0xE03A0015 error (Goog/Bing search turns up nothing). Otherwise Hyper-V is still functional on the host, but this problem makes me a little nervous.

    Thanks!


    / David
    Thursday, August 20, 2009 9:18 AM

Answers

  • After months of problems I have finally found the solution - in this thread. The root cause was that a Group Policy had overridden the security groups that are allowed to create symbolic links. In order for Hyper-V to work, the group Virtual Machines must have this right, in addition to Administrators. Without this right, it is not possible to create snapshots or new virtual machines.
    What made this so hard to diagnose was that Process Monitor (at least the version I was using) didn't report the failure to create a symbolic link. Now all is good again, but I do have one question:

    Why is the Virtual Machines security group so special? I can't select it in the security editor in order to add permissions manually to files and folders. Moreover, specifying Virtual Machines in the domain's Group Policy won't work - the group will get filtered and not applied locally. Instead the Create symbolic link User Right Assignment must not be applied on Group Policy level, so the Local Policy gets precedence (which is configured correctly by the Hyper-V installation).

    Anyway, now you know what error 0xE03A0015 really means.
    / David
    • Marked as answer by Vincent Hu Monday, November 16, 2009 9:11 AM
    Thursday, November 12, 2009 11:30 AM

All replies

  • Hi,

    Please refer to the following:

    Event ID 16370 — Virtual Machine Snapshot Operation
    http://technet.microsoft.com/en-us/library/dd582372(WS.10).aspx
    Friday, August 21, 2009 10:22 AM
  • Thanks Pravin,

    I have studied that documentation and tried to eliminate the possible causes described: There is enough free space on all disks, the filesystem has no errors, and I see no other suspicous events in the log. I upgraded to SP2 back in June, and I suspect that this is what triggered the error. Right now the VMMS log fills up with messages about missing snapshots, probably from my failed attempts at creating them. Apart from finding the cause of this error and fixing it I need a way to get Hyper-V back into a consistent state where it stops looking for snapshots that don't exist.

    (One would think that snapshot creation operations were more transactional in nature, so that it was impossible to get into this inconsistent state where the snapshots are recorded somewhere but don't exist on disk or can't be seen in the VM configuration. After all, there is transactional Registry and NTFS now...)
    / David
    Friday, August 21, 2009 12:13 PM
  • After months of problems I have finally found the solution - in this thread. The root cause was that a Group Policy had overridden the security groups that are allowed to create symbolic links. In order for Hyper-V to work, the group Virtual Machines must have this right, in addition to Administrators. Without this right, it is not possible to create snapshots or new virtual machines.
    What made this so hard to diagnose was that Process Monitor (at least the version I was using) didn't report the failure to create a symbolic link. Now all is good again, but I do have one question:

    Why is the Virtual Machines security group so special? I can't select it in the security editor in order to add permissions manually to files and folders. Moreover, specifying Virtual Machines in the domain's Group Policy won't work - the group will get filtered and not applied locally. Instead the Create symbolic link User Right Assignment must not be applied on Group Policy level, so the Local Policy gets precedence (which is configured correctly by the Hyper-V installation).

    Anyway, now you know what error 0xE03A0015 really means.
    / David
    • Marked as answer by Vincent Hu Monday, November 16, 2009 9:11 AM
    Thursday, November 12, 2009 11:30 AM