Changing BIOS from Legacy to UEFI/BIOS so I can use Win 11 on this PC

Hi, assuming your existing installation is indeed legacy BIOS (evidence needed first) what you are asking is very far from simple and avoiding 'computerese' is impossible.

Assuming it is, you would have to use this, for example:
Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

and once you have UEFI configured, to enable Seecure Boot see:
Enable Secure Boot to protect systems from UEFI rootkit ‘CosmicStrand’ | Security & Technical Advisory - GIGABYTE Global

That's just to give you some idea.

As a starting point, you'd need to provide evidence of exactly what you have configured now. You might start by posting a screenshot of your existing O/S partitions:
How to Post a Screenshot of Disk Management

and for completeness:
Check if Windows 10 is using UEFI or Legacy BIOS

Considering possible compatibility issues related to the upgrade to Win 11, get a copy of this, run it and post a screenshot:
Download WhyNotWin11 - MajorGeeks

To post a screenshot on tenforums please use this icon (above your post as you type it):


Because the above carries risk and is a major change, you should first clone your system disk, and then make changes to the cloned disk.

If you attempt this on your existing system disk rather than a copy of it, you could well destroy your O/S.

therealsimpsons said:

I think I did it right, thanks. I have no idea what it means.

It means that only Disk 2 is currently... GPT

therealsimpsons said:

What is GPT? How do I know which one of my drives is Disk 2? I have a C drive, SSD 1TB. I have an F drive, SATA 1 TB. Both of those are internal. My Windows 10 is on C Drive. The other two drives are external. If I unplug them, I assume they will not show up on the list of disks.

Post a screenshot of Disk Management. That will tell us.

A proper screen shot of Disk Management will look like this.
The Disk Management windows must be resized so we can read .... everything...


These are MY screen shots, from MY computer.











YOUR Disk 2 is the 4TB disk. <------------------------

But please post a Disk Management screen shot... anyway.

therealsimpsons said:

Hope you can read it..

I can read it.


On your system you have the System reserved partition and the C:\ partition on different disks.
I'm not sure if that will work.

Open a command prompt as Admin ant type this command...

mbr2gpt /validate | convert /disk:1

The post a screen shot of the result.

If I got the command right... this will tell us if the mbr2gpt command will work on Disk 1

If I got the command wrong... it will just throw an error... it won't hurt anything.



These are the mbr2gpt options available...