Yesterday I wasted way too much hours migrating some VMs from Windows 10 to Windows 11, since I ran into some obscure problems.
Maybe this helps someone else, because I could not find good information on my specific problems in the forums nor on reddit.
What was "special" about my migration?
mbr2gpt did not work.
From a previous disk expansion, I deleted some recovery partitions.
And for reasons unknown to me, my first system reserved partition was only 50mb in size.
This might have broken the tool mbr2gpt, which is used to convert MBR to GPT, which is a requirement for Windows 11.
Here is what worked for me:
Open cmd as admin.
Enter:
If you get no errors, congrats
If you get an error, maybe something like I got:
you need to do some extra next steps.
Otherwise you can just issue
and shutdown the VM and jump to the "BIOS to OVMF" part.
One possible solution would be to delete every partition expect system reserved and C: Windows
To do that open cmd as admin.
I have not needed it but some say that you should run this command
to disable the recovery. But like I said, I don't have recovery partitions for my VMs.
We enter
you should so only two partition. If you have three partitions and the last one is a recovery partition, you might remove it by entering:
shutdown the VM, take a snapshot, and reboot the VM.
Here is another step that was needed for me to get mbr2gpt working:
In my case, I only have a 50mb system reserved partition and a C: partition that is not marked as active for some reason.
This makes mbr2gpt not recognize the OS. To solve this, we simply enter:
and press enter to exit diskpart.
rebuild boot by running
If we now run
there should be no error.
We can now issue:
you can ignore the WinRe repair error if you like me don't have a recovery partition.
Shutdown the VM.
Take a snapshot.
Change the BIOS to OVMF
in the PVE settings.
Add an EFI and add a TPM drive.
Change the machine type below to q35 and 8.1 or whatever you like. Just make sure it is above 6 to get support throughout PVE9.
Try to boot the VM. If the VM boots, we should be almost done.
Check with the Windows Health App again what is still missing.
If it is the CPU, shutdown the VM.
Set the CPU to x86-64-v2 or higher.
x86-64-v23 should work for most not very old CPUs.
For very modern CPUs you might even be able to use x86-64-v4.
If your CPU does not support it, you will see an error when you try to boot the VM.
Take a snapshot.
Boot the VM again.
If your Windows does not boot but gives you a bluescreen, try to boot into secure mode or just reboot the VM and try again. In most cases that should work.
Check again with the health app.
You should now be able to upgrade to Windows 11.
Maybe this helps someone else, because I could not find good information on my specific problems in the forums nor on reddit.
What was "special" about my migration?
mbr2gpt did not work.
From a previous disk expansion, I deleted some recovery partitions.
And for reasons unknown to me, my first system reserved partition was only 50mb in size.
This might have broken the tool mbr2gpt, which is used to convert MBR to GPT, which is a requirement for Windows 11.
Here is what worked for me:
Open cmd as admin.
Enter:
mbr2gpt /validate /disk:0 /allowfullosIf you get no errors, congrats
If you get an error, maybe something like I got:
Cannot find OS partition(s) for disk 0you need to do some extra next steps.
Otherwise you can just issue
mbr2gpt /convert /disk:0 /allowfullosand shutdown the VM and jump to the "BIOS to OVMF" part.
One possible solution would be to delete every partition expect system reserved and C: Windows
To do that open cmd as admin.
I have not needed it but some say that you should run this command
reagentc /disableto disable the recovery. But like I said, I don't have recovery partitions for my VMs.
We enter
Code:
diskpart
list disk
select disk
list partitionyou should so only two partition. If you have three partitions and the last one is a recovery partition, you might remove it by entering:
Code:
select partition 3
delete partition override
quitshutdown the VM, take a snapshot, and reboot the VM.
Here is another step that was needed for me to get mbr2gpt working:
In my case, I only have a 50mb system reserved partition and a C: partition that is not marked as active for some reason.
This makes mbr2gpt not recognize the OS. To solve this, we simply enter:
Code:
diskpart
select disk 0
select partition 2
active
exitrebuild boot by running
bcdboot C:\Windows /s C: /f BIOSIf we now run
mbr2gpt /validate /disk:0 /allowfullosthere should be no error.
We can now issue:
mbr2gpt /convert /disk:0 /allowfullosyou can ignore the WinRe repair error if you like me don't have a recovery partition.
Shutdown the VM.
Take a snapshot.
Change the BIOS to OVMF
in the PVE settings.
Add an EFI and add a TPM drive.
Change the machine type below to q35 and 8.1 or whatever you like. Just make sure it is above 6 to get support throughout PVE9.
Try to boot the VM. If the VM boots, we should be almost done.
Check with the Windows Health App again what is still missing.
If it is the CPU, shutdown the VM.
Set the CPU to x86-64-v2 or higher.
x86-64-v23 should work for most not very old CPUs.
For very modern CPUs you might even be able to use x86-64-v4.
If your CPU does not support it, you will see an error when you try to boot the VM.
Take a snapshot.
Boot the VM again.
If your Windows does not boot but gives you a bluescreen, try to boot into secure mode or just reboot the VM and try again. In most cases that should work.
Check again with the health app.
You should now be able to upgrade to Windows 11.
Last edited:
