A perennial problem with a Hyper-V VM failing to start

Question

I keep getting an error when starting a particular virtual machine on Hyper-V.

The error:

'VSERVER' failed to start.

Synthetic SCSI controller (Instance ID XXXXX): Failed to Power on with Error 'The chain of virtual hard disks is corrupted. There is a mismatch in the identifiers of the parent virtual hard disk and differencing disk'.

The problem is fixed via this command:

Set-VHD "C:\Path\to\Hyper-V\VSERVER.avhdx" -ParentPath "C:\Path\to\Hyper-V\VSERVER.vhdx" -ignoreidmismatch

...and the VM will start right up again.

But after a random #s of shutdowns, the "VSERVER failed to start" error will crop up again and I have to go thru this whole process over again.

How do I prevent this in the future?

The VM is Gen 2, checkpoints are disabled, all integration services offered, configuration version is 8.

Hyper-V Manager is version 10.0.17763.1, Windows Server 2019 version 1809 (OS build 17763.6054).

Windows Update is up to date.

Thanks!

Side note: I've noticed that if I shut down the VM from within the VM (i.e. at the cmd prompt), it so far hasn't caused this error. I think, I'm not 100% sure, only because I just noticed that the VM has restarted fine the past 2 or 3 times I've done it this way. However (and I can't say this happens all the time), if I use Shut Down from the Hyper-V manager, and try to restart, it *appears* to result in the error. I think. I don't want to keep experimenting this way in case the error is indicative of a more serious underlying issue and I end up REALLY breaking things.

Answer 1

Hi，

Please create a new VM with the same configuration and attach the virtual disks to that to see if the issue persists.

Also delete all the checkpoints in Hyper-V manager. If the checkpoints cannot be deleted, you may have to merge them manually. Please refer to this link for more details.

How to merge checkpoints that have multiple differencing disks - Windows Server | Microsoft Learn

Don't forget to back up the virtual disk files before any operation.

Answer 2

OK, I actually used a set of instructions from Microsoft that I got on a different community page that utilizes "Edit Disk..." right in Hyper-V manager (https://learn.microsoft.com/en-us/archive/technet-wiki/6257.manually-merge-avhd-to-vhd-in-hyper-v).  I had asked this question in 2 locations, and I used this answer first.

Anyway, there were 2 .avhdx files and the parent .vhdx file. I managed to merge the "grandchild" (for a lack of a better term) to its parent just fine. But merging the last .avhdx file to its parent gave me "An internal error occurred. (0x8007054F)" The event viewer gives these details: "The system cannot find the file specified. (0x80070002)". I'm assuming the "missing file" was the first .avhdx file?

What's my next step now?

Thanks!

Answer 3

Hi andy9999,

Please open CMD as administrator and run chkdsk /r to fix logical and physical disk errors.

In Hyper-V Manager, select Edit Disk > Merge > To a new virtual hard disk to see if the avhdx file can be merged.