Switch from BIOS to UEFI for Existing Windows 10 Virual Machine

[chcw]

Hi,

Currently I am using VMWare Workstation Pro 12.5.7.

I have installed Windows 10 Professional(64bit) on a Virutal Machine and use BIOS as the boot method.

However, now I want to upgrade to Windows 11 and it says I need to change to UEFI secure boot to support such an upgrade.

So I try to go to "Settings -> Advanced -> Boot with EFI instead of BIOS" and enable this option.

However, when I restart the computer, I see the following info:

After that, I see the following screen:

So, what should I do for such a case?

[bluefirestorm · Accepted solution]

Before switching to UEFI, you need to convert the disk structure from MBR to GPT. UEFI will require a GPT disk to boot.

You use the MBR2GPT tool to do the conversion.
https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

So switch back to BIOS, boot the Windows 10 VM up, convert using MBR2GPT, then switch to UEFI.

If you want to play safe, back up the VM or at least back up the data/stuff inside that is important to you,

[chcw]

Thank you. Your solution works perfectly.

Howeve, even after a successful conversion, after I reboot the system with "EFI" option. It seems still not work. See https://communities.vmware.com/t5/VMware-Workstation-Pro/Can-quot-Boot-with-EFI-quot-work-as-quot-Se...

[bluefirestorm · Accepted solution]

You're using a very old version of Workstation Pro.

Version 12.5.7 was the last update for 12.5.x series in early 2018 because of the Intel CPU Spectre bugs. I don't think 12.5.7 supports Secure Boot. If I am not mistaken, Secure Boot and virtual TPM (another Windows 11 requirement) was introduced with Workstation Pro 14.x.

Note that Worsktation 14.x and newer require Intel CPUs from Westmere microarchitecture (2010) or newer, Is that why you are still using 12.5.7?

You could try the registry bypass tricks for installing Windows 11 without secure boot and TPM. You can search the web for Windows 11 secure boot TPM bypass.