I am slowing going through and removing snapshots that for some inexplicable reason have been running since 2012!!!!!!!

Most have been fine to delete and let the merge happen offline or at worst export and import the machine. I am left with a single server that has a whomping 150GB snapshot that keeps generating the following error:


I get the same error when I try and export the machine. I cant find anything online to describe this and the "unspecified error" is really frustrating. Has anyone else seen this behaviour before or have any clever workarounds?


So looking at it all files are on the same mounted volume. There are two AVHD files though (both over 100GB!!!!!) but only one snapshot showing in Hyper-V. I am wondering if the orphaned snapshot is causing the issue. Downside is the VHD has a modified date after the first VHD so something has been botched on this machine..

  • How much free space do you have on the volume where the VHD9X) and snapshot exists? – joeqwerty Jul 11 '15 at 17:30
  • Couple of terabytes I think but will need to check that all the vm files on that volume – Tim Alexander Jul 11 '15 at 17:33
  • That's a lot of snapshot data! – john Jul 11 '15 at 18:31

I don't have the solution to your specific problem, but since you mention workarounds....

When I have an issue like this, I often find it easier just to merge the disks manually and, if necessary, create a new virtual machine from the disks. In Hyper-V manager's edit disk wizard you can select the AVHD and you will have the option to merge into the parent VHD.

Guide here: https://exchangeservergeeks.wordpress.com/2014/02/21/hyper-v-avhd-manual-merging-steps/

This won't get around your issue with removing the snapshot as the VM will still think it has a snapshot (and the VM will be pointed at the AVHDs still). Essentially you'd need to create a new VM from the manually merged disks.

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