Windows 10: Convert Windows 10 Legacy BIOS to UEFI

MBR2GPT will not run because there are too many partitions on my HDD C:. How would I reduce the number of partitions or if I clone the drive to a new drive does it just move data or does the cloning also move the partitions?

:)

 

Convert an existing Windows 10 Installation from Legacy BIOS to UEFI

Convert an existing Windows 10 Installation from Legacy BIOS to UEFI without using 3rd party software.

 

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.