Upgrade a Windows 10 Proxmox VM to Windows 11

With the end of life date quickly approaching, I decided it was time to make a post about upgrading a Windows 10 VM to Windows 11.

Before you begin, I would suggest taking a backup or snapshot of your current system should something go wrong.

To begin, download the Windows 11 ISO. You can get this from Microsoft's website. Mount this to your VM as a CD.

Convert to UEFI

Open an admin Powershell window

mbr2gpt /validate /allowFullOS

If the above fails validation, run chkdsk /f C: as well as sfc /scannow then try running the above validation command again

If the above validates successfully then...

mbr2gpt /convert /disk:0 /allowFullOS

Shutdown the VM

Change BIOS from SeaBIOS to OVMF (UEFI) on the Hardware tab under BIOS

Create an EFI disk making sure Pre-Enroll keys is ticked

Create a TPM disk. V2.0 for Windows 11

Finally, boot your VM back up and you should boot back into Windows 10 but with UEFI now

Windows 11 Upgrade

Run the setup.exe from the CD you mounted at the beginning, run through the setup and you should get through all the checks as you now have Secure Boot, UEFI and TPM. A few reboots later and you should be in Windows 11. You can remove the CD again once done.