Windows 10: I can't convert Legacy to UEFI I literally tried everything I always get errors.

So I need help because I can't upgrade to Windows 11 since I have Legacy for my BIOS and Win11 doesn't support it. I tried doing the mbr2gpt command on the prompt, no luck at all, just got errors like failing to convert to UEFI, or could not find the disk, I tried using AOMEI and it says they strongly recommend that I don't do it because Windows won't boot anymore if I do so, and even MiniTool Partition Wizard tells me I have over 2TB so I can't copy partition wizard. I tried everything, I'm literally out of ideas. My BIOS and motherboard are from MSI. If I switch it from the BIOS the PC won't

:)

 

Convert UEFI to Legacy for Windows 7 installation

I have Ideapad 330s with Windows 10 64-bit pre-installed out of box in
UEFI mode and GPT partition style .

i tried to boot Windows 7 64 bit GPT style via Bootable USB but it shows an error
0x000000d : an error occurred while attempting to read the boot configuration data .

do need to convert UEFI mode to Legacy ?

and the partition style from GPT to MBR ?

i don't know how to proceed with Windows 7 installation.

Please Help.

 

Convert Windows 10 from Legacy BIOS to UEFI without Data Loss  


Matter solved, thanks!

FWIW ...

[Screenshot 1]
From admin command prompt

mbr2gpt /validate /allowFullOS

and then:

mbr2gpt /convert /allowfullOS






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[Screenshot 2]
From admin command prompt

Diskpart
List Disk

shows the converted drive (disk 1)





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[Screenshot 3]
Run msinfo32
shows that now UEFI is enabled to boot from.





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[Screenshot 4]
run dskmgmt
before and after - shows an extra partition





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[Screenshot 5]
Motherboard BIOS (Asus X99 DeLuxe/U3.1)
select Boot section in BIOS
select CSM
select Enabled
select UEFI and legacy OpROM

'Enabled' and 'UEFI and legacy OpROM' were already selected in my case)
(tried UEFI only, but that disables the keyboard)




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Small note:
In my case the steps outlined in "How to Boot to UEFI Firmware Settings from inside Windows 10" didn't work.
Start->Settings->Update & Security->Recovery->Restart Now (Advanced Startup)->Troubleshoot->Advanced Options...

from this point on Windows restarted ("Please Wait" and "Turning off your computer"), instead of 'Startup settings",
instead of getting "UEFI Firmware Settings".

Anyway, matter solved.

 

Convert Windows 10 from Legacy BIOS to UEFI without Data Loss  

For clarity, you can only change UEFI settings if already booted to UEFI. If booted as legacy bios, that option does not exist.