Hyper-V Virtual Machines disappear after rebooting

Question

Hi. I have two servers, one is a Windows Server 2019 with the Hyper-V role and another is a Windows 2016 Server with the Hyper-V role installed. All of my virtual machines are configuration version 8.0. I setup Hyper-V replication to replicate the Virtual Machines on the 2019 host to the 2016 host. This works fine and replicates the VM's I have selected. When I reboot the Windows 2016 server I notice that in the Hyper-V Manager console all the Virtual Machines that had been replicated are gone and do not show up. I found other articles to check the folder C:\ProgramData\Microsoft\Windows\Hyper-V\Virtual Machines for symbolic links however this folder is completely empty. I checked the drive location where I setup the replication and the virtual machines and virtual hard disks are there, so I know the data still exists but why are all the VM's gone? I don't find anything in the event log to indicate an issue, and I have reformatted the 2016 Hyper-V host with a clean install and run into the same issue. Any ideas on why and how to fix this?

Answer 1

Hi All

I have this too, the magical disappearing VM that was replicated between 2019 and 2016.
as soon as I restart the Hyper-V Virtual Machine Management (vmms) service its gone from the hyper-V manager.

I even reinstalled both hosts thinking I had corrupted something.

All the virtual machines that where not replicating are fine but the server I was replicating (web2) is at the bottom of the list so its possible if I have more under it they would disappear too.

The server is still active thou, I can rdp on to it and it continues to function as if everything is fine.
To get the server to show up in the management control again temporarily (as lest until the vmms service is rebooted) I did find a trick thou for anyone that may need it back for a moment for exports or what ever.

log in to the virtual server that disappeared and shut it down, then stop the vmms service. rename the folder the virtual machine lives in to something else. start the vmms service. the server will be back in a critical error state. rename the virtual machine home back to its original name and you will then be able to boot the server.

I guess I will have to try and convince my client to fork out for new OS just to get something working that apparently should work between 2019 and 2016. if anyone has a fix for this before i have to have this conversation with that would be dandy

Thanks all

Regards
Torben
Data management solutions IT

Answer 2

I just wanted to weigh in. I have two Win server 2019 of same build. They receive same windows updates but and they are in a hyper-v replication relationship. The primary server will allways fail showing the same VM's every time. So if I don't watch it and receives the monthly update they will fail of showing in HyperV Manager the next boot. Though the VM work as expected from customer POV, the backup will fail and it's not a viable condition to have. So the short term solution would be removing the last month CU and reboot. I suspect it could be the VM configuration version giving this headeach since the VMs in trouble have version 8 and the others are on version 9. I'll admit it's a little strange since they appear on the secondary host (though turned off). Be carefull to raise the configuration level if there are different OS on the Hyper-V hosts. That way you won't be able to replicate back.

Answer 3

This posting was for an issue with Win 2019 to Win 2016 issue. I believe yours is different and you might want to post a new question.

Answer 4

I think MS is never going to fix this issue. It is just a lesson to be learned about 2016 to 2019.

Answer 5

I'm confirming this issue still exists in Windows Server 2016.

We recently experienced this same problem: replicating virtual machines to a Windows Server 2016 machine from a server running Windows Server 2019 or Windows Server 2022. Virtual machines would disappear entirely from the Hyper-V Manager, upon reboot or after restarting the "Hyper V Virtual Machine Management" service. (The VMCS and VHDX files are still present on the disk.)

We were able to bypass this bug by doing an in-place upgrade of the replication server from Windows Server 2016 to Windows Server 2019. Post-upgrade/reboot, the issue no longer exists, and the missing VMs magically re-appeared.