How to convert Hyper-V Server 2019 boot method, from BIOS to UEFI

Question

I have installed Hyper-V Server 2019 in a machine and it turns out that I didn't have the BIOS switched to UEFI boot.
So, it was installed with BIOS boot. (what is wrong with the people choosing the default values anyway...? :| )
Since I have spent a fair amount of time updating the machine and configuring it, I am thinking of switching to UEFI boot with a conversion instead of a reinstall.

I have found this interesting article:
https://www.windowscentral.com/how-convert-mbr-disk-gpt-move-bios-uefi-windows-10

The second method will probably work, but it is not recommended.
The first method is recommended, but it uses Windows GUI components that are missing from Hyper-V Server.
On top of that, mbr2gpt seems to be missing too, in Hyper-V Server.

So, does anyone have any suggestions for this?

1) Is the first method applicable to Hyper-V somehow?
2) Can I instead boot from a Windows10/WindowsServer2019 DVD, switch to GPT with mbr2gpt and have this transition?
3) Is it better to reinstall?
4) Can the conversion to GPT affect the future performance of the drive (compared to using a reinstall)?
5) I guess that, if I want to reinstall the OS, I should export the VM to an external drive or shared network location, right? Copying the VM files and config manually, will probably not be a good idea.

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BTW, Hyper-V Server seems awesome!
I like the fact that one can manage it from WAC, the fact that it is Windows and the update is easy, the fact that it is free, the fact that you can manage it using PowerShell.

It has some rough edges though.
E.g., I recently tried to attach an ISO to a virtual DVD, and I couldn't.
The reason turned out to be that the ISO was on a DVD drive.
I needed to copy the ISO on the OS drive.
The UI of WAC was not so helpful to figure things out.
And I am not sure why I couldn't attach it from the DVD drive to begin with, nor if this is a problem with WAC or Hyper-V, but anyway...

Answer 1

Simplest / safest solution would be to export / save the virtual machines off somewhere, clean install the operating system, patch fully, add hyper-v role, import virtual machines.

--please don't forget to Accept as answer if the reply is helpful--

Answer 2

Hi,

It's highly recommended to reinstall the OS to be UEFI boot instead of converting it.

We may export the VM into an external drive, then reinstall the OS of the Hyper V host, then import back the VMs.

Thanks for your time!
Best Regards,
Anne

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