[Solved] Convert guest from legacy boot to uefi boot

Discussions about using Windows guests in VirtualBox.
Post Reply
Shmu26
Posts: 99
Joined: 21. Dec 2017, 15:32

[Solved] Convert guest from legacy boot to uefi boot

Post by Shmu26 »

I have a Windows 10 guest that uses legacy boot. I would like to convert it to uefi boot. How?
The goal is better compatibility with upcoming Windows 11. At this point, an Insider dev version of Win11 will still run in a VM with legacy boot, but it shows an ominous warning sign.
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Convert guest from legacy boot to uefi boot

Post by mpack »

Shmu26 wrote:I have a Windows 10 guest that uses legacy boot. I would like to convert it to uefi boot. How?
Try Google. The procedure for a VM will be no different to any other PC.

Personally I'd try making a Macrium backup and then restore it into an EFI-enabled VM.

And bear in mind that if Microsoft restrict themselves to UEFI machines then they'd be limiting their own market, at least to some extent. I frankly don't know if legacy BIOS numbers are still significant.
Shmu26
Posts: 99
Joined: 21. Dec 2017, 15:32

Re: Convert guest from legacy boot to uefi boot

Post by Shmu26 »

Thanks. The Macrium Reflect way sounds good.
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Convert guest from legacy boot to uefi boot

Post by mpack »

Bear in mind that I've only said that this is what I'd try. I'm not guaranteeing that it will work. Macrium has the ability to make many corrections to the backup when restoring it into slightly incompatible systems. ISTR that included in this is conversion between MBR and UEFI boots, but I could be wrong.

Also, you may find that a UEFI BIOS is quite capable of booting a disk which uses MBR partitions. Only the reverse is not possible (MBR definitely does not support GPT).
Shmu26
Posts: 99
Joined: 21. Dec 2017, 15:32

Re: Convert guest from legacy boot to uefi boot

Post by Shmu26 »

If you don't hear from me again, it worked. I am in the middle of the job. I saved the Macrium backup onto a GPT disk, and I am restoring it onto a GPT disk. It should work because I did something similar once with a physical system.
Shmu26
Posts: 99
Joined: 21. Dec 2017, 15:32

Re: Convert guest from legacy boot to uefi boot

Post by Shmu26 »

After restoring the image I just needed to run Macrium Reflect boot repair, and then everything worked. :)
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Convert guest from legacy boot to uefi boot

Post by mpack »

Great - I'm glad to hear that the suggestion worked.
Shmu26
Posts: 99
Joined: 21. Dec 2017, 15:32

Re: [Solved] Convert guest from legacy boot to uefi boot

Post by Shmu26 »

Shmu26 wrote:At this point, an Insider dev version of Win11 will still run in a VM with legacy boot, but it shows an ominous warning sign.
Although the current hardware security requirements for Windows 11 are rather high:
1 UEFI
2 Secure boot
3 TPM 2.0

this was not the cause of the warning sign I saw in Windows security center on Win11. It was rather caused by a known bug in the current Insider dev versions: after every reboot, "Automatic sample submission" turns itself off. It needs to be enabled manually, or alternatively, to use a registry hack. Then the warning sign goes away.

The upshot is that the above hardware requirements apparently are not being enforced in VMs, which makes sense.
Post Reply