Hyper-V Missing VMs

Over the past 6 months I installed 4 Server 2019 Hyper-V hosts for various clients. After several months with no problems, following a reboot, all running VM’s completely disappeared from the Hyper-V management console and were not accessible from the network using management tools, file shares, remote desktop, or even pings. Oddly, shut down or saved VM’s were present.

When this first happened I was shocked. The VHDX files were all present so I could create a new VM, but that didn’t seem practical. Googling showed that this can happen if the Hyper-V Virtual Machine Management service did not start, but in my case it had. I tried restarting the service, the VM’s instantly reappeared, and were in a running state with boot up almost complete.

This issue over the coming months started happening on other 2019 servers and after every reboot, planned or due to a power outage, I had to connect to the host and restart the Hyper-V Virtual Machine Management service.

Further Googling this issue brings up suggestions of corrupt VM configuration files, granting “NT Virtual Machine\Virtual Machines” the “logon as a service right”, doing the same with group policy, and other suggestions, but where restarting the service would resolve in every case I assumed there was not a configuration issue.

In the end setting the Hyper-V Virtual Machine Management service start up type to “Automatic (delayed start)” resolved the problem on all machines, though it resulted in a slightly longer boot time for the VMs.

All of thee servers worked fine for a few months so I assume the problem was due to a Windows update but to date I have found no actual cause. Also, I can confirm this only occurs on my 2019 Hyper-V hosts. There are no issues with Server 2016 or earlier servers.

Hyper-V restart

Update: Oct 2020. I had another server with the same issue. O/S had been installed 8 months prior and no updates applied in recent months. Setting the service as delayed start did not resolve. I had to create a scheduled task to run 10 minutes after boot up. 5 minutes did not work. The scheduled task simply pointed to a batch file with the following. (the ping command just delays the process to be sure Net Stop completes before the next line).

Net Stop VMMS
ping -n 10 127.0.0.1
Net Start VMMS
Exit

Comments on: "Hyper-V Missing VMs" (6)

  1. Gday, I can confirm I’ve run into this issue recently, no idea what is the cause. Delayed start for VMMS didn’t make a difference. At the moment the only solution I have is a scheduled task on boot which will stop the VMMS and then start it again, once that happens, presto VM’s are visible and all start up.
    Did you ever get any further to finding a cause?
    Regards,
    Steve

    • Hi Steve. The delayed start seems to have resolved for me but I can see a scheduled task working as you have done. It is very odd. I set up about 5 2019 servers over a 8 month period and everyone started doing the same thing after 3-4 months. I initially thought it was a Windows update but I apply all updates when setting up a server so the latter ones would have had the previous updates installed initially. I haven’t set any up since the pandemic to see if the same issue persists on new servers. I don’t know if it is relevant, but all servers were HP, though not all the same model. No firmware updates were applied after the initial installation.

      • glimmerman101 said:

        Hi Rob, this server is a HP also, Proliant ML350 G10. I thought it was a Windows updates as we have a few more updates installed on this particular host compared to the other host machine in this environment (both deployed at the same time, same model etc) – at this stage no other 2019 machines exhibit this.
        Thanks for your response, I might have a look further at the HP side of things and see if any drivers or BIOS etc list issues with HYPER-V.

      • glimmerman101 said:

        I’m also considering rebuilding one of these hosts – did you ever go through this and find it was a solution or the delayed restart wasn’t enough of a hinderance to warrant it?

        What we have found the only error in the event logs:

        Cannot load a virtual machine configuration: The request is not supported. (0x80070032). (Virtual machine ID 6C3CC124-1C92-4206-9F45-D1992AE05312)

        – This has led to a bunch of dead ends at this stage looking up the above error.

        I may contact MS support and lodge a case with them also.

  2. I haven’t rebuilt any of the servers. Reboots are done during off hours so the slightly longer boot hasn’t been a problem. Tempted to remove the delayed start and see if the problem persists or maybe a more recent update has resolved.

    I just realized I installed 2019 as a host on an older *Dell* server in my office the end of February and it hasn’t been a problem……yet. Anxious to hear if you learn anything new. Thanks for your feedback.

  3. Steve, just an update. The Dell server I mentioned which didn’t have any issues started exhibiting the same problem of “No virtual machines found on this server” this morning, after a forced reboot (power outages), but on a UPS. This is 8 months after built and no updates applied for more that 12 weeks except antivirus. I confess I do not apply updates regularly on host servers.

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