Process for Converting from Legacy to UEFI (in prep for Win 11)

Furthermore, on a separate machine with Parallels and running an unrelated VM created fresh with Windows 10 (not upgraded), the first partition begins in exactly the same place. So now I am wondering why many more people are not seeing this error when trying to perform this process?

 

Just wanted to say that the original procedure posted here worked great on two different Win10 VMs on two different Macs, thank you @Mark Fine!

 

Now that Paralles has introduced the facility to add TPM within its software (see https://kb.parallels.com/en/122702), does this mean that the procedure outlined above is now redundant?

 

I doubt it. The software has always had a facility to add TPM. I just didn't work in many instances because Windows itself wasn't prepped properly.

 

@Consonanza., @Mark Fine is correct: this thread isn't about adding TPM per se, but rather converting from Legacy to UEFI with existing VMs. You'll see a section at the bottom of that article under Troubleshooting called TPM chip is not on the list, and you'll see that the article says to just create a new VM (i.e. not use your existing VM with all your data in it!). That's the case where the procedure that @Mark Fine created solves a problem.

 

I am getting a failure to validate when running the mbr2gpt utility, presumably because I have 4 partitions ... see screen shot. When I go to delete one (This is a test VM) I get a message, as per screenshot that the partition is related to other systems on the disk. I am concerned I may wreck my Mac disk. Admit I don't understand what the Disk Mgmt utility is looking at. Are all these partitions within the VM or am I at risk here deleting partitions?

 

Simething strange here based on further investigation. Disk appears to be GPT but partitions are MBR. Abyone assist?

 

I've run through the procedure twice (got the RE error as described but all else was as expected). Both times, the VM does not boot and I get the below. I also added "vm.bios.efi=0" under advanced in Boot Options. I'l running Parallels 18. Any thoughts?

 

Same for me. No Issues. Many thanks to Mark and Brian.

 

Hi I know it is rather late, where you able to convert to UEFI?
I have the same issue, mine VM is created from a Bootcamp partition.

Thank you.

 

Unfortunately no, This VM remains on Win 10. I eventually migrated everthing to a fresh VM of Win 11.

 

No. My first partition is too close to the head of the drive and no one can tell me how to move it back to a position where the Windows tool can upgrade it.
I consigned myself to never being able to upgrade my VM to Windows 11. Since I don't relish starting from zero to assemble yet another Windows system that has all the tools I need, I'll just run 10 until it falls apart.
Windows not having a file-migration facility is simply monstrously user-hostile.

 

Hi, I managed to convert my virtual disk and then upgrade.
It requires to remove the not used partition, move the windows bootcamp portion and then delete the EFUI portion in a Linux Virtual Machine (VM). Then booting the windows VM with a recovery usb stick and create a new EFI partition with diskpart and use bcdboot to populate the new EFI partition. You can the upgrade to Windows 11.
Let me know if you are convertible in linux and moving virtual disks around in VMs.
I can dan provide a more or less detailed instruction.

 

This worked like magic and was a quick process. I'm dealing with an ancient (2012) VM running Windows 10, but very poorly. Tech support recommended a new VM but I didn't want to reinstall and reconfigure every program and plug-in. I followed this process to see if the W11 upgrade would rejuvenate the performance of my VM. I'm at 80% install, so hopefully I have good new to report.