We have a development environment that started out running on Windows Server 2012.  Since its a development environment with local attached storage (NOT SAN) and a lot of snapshot/checkpoints on the VMs we set it up a bit differently than you would a production Hyper-V environment. The VMs are all setup with dynamic VHDX files located in their own partition, the partition is mapped to a path c:\VMs\VMName.  This worked great under WS 2008 R2 and WS 2012.

Then we upgraded to WS 2012 R2.  When we did that we started noticing a problem with VMs with checkpoints.  Applying to different checkpoints in the same VM would often fail.  The error tracked down to not being able to find the AVHDX files generally.

So we got a new server in and set it up with WS 2012 R2 and set it up the same way with mounted paths to the partition.  Same problem occurred.  I then took the same VHDX file and set up a new VM on the same machine and used a drive letter mapped to the partition and no problems at all.   So it looks like the issue is using path mounts for the partitions instead of drive letters.

We went to this system largely because it let us get away with smaller partitions without worries of disk fragmentation.  Yes I know WS 2012 does disk defragmentation, but if you can avoid the issue in the first place...  Our other issue is we have more than 26 VMs so there aren't enough letters available to do the job unless we start putting multiple VMs on a partition.

I tried searching for a KB article but came up blank, largely probably because of the huge number of hits a search like this would turn up for everything but what I want.  I can figure out a workaround, but what I'd really like is a fix.  Has anyone seen this?

Thanks in advance for any

A bit of additional information.  If the VM isn't using a checkpoint we don't have any problems using mount paths.  Its only with checkpoints we have problems.

Also, the VMs are set to store all information in the same location.  I suppose we could choose to put the AVDHX files in a directory mapped to a drive l

Hi,

I am trying to involve someone more familiar with this issue. There might be some time delay. Appreciate your patience.

Thanks for your understanding and support.

Hi Bob,

I see the mounted disk in your environment is dynamic disk type, could you try to mount a basic disk to the C:\VMs folder, if it still have the simlar issue please feel free let us know.

The related KB:

Basic and Dynamic Disks

https://msdn.microsoft.com/en-us/library/windows/desktop/aa363785%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396

Im glad to be of help to you!