Windows 10: Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

*Eek Oki doki.

 

Hoping for some help figuring out my issue.
MBR2GPT is not able to validate my disk.
The error says:
Cannot map MBR partition type 238. Please supply custom mapping through the command line.
First partition too close to the beginning of the disk. Should start at offset 17408 or above, found at 512









Any thoughts?

 

It's probably the GPT Protective Partition, but it is really weird that it is only a small part of the drive:
How to Access GPT Protective Partition Without Losing Data Windows 10/8/7 - EaseUS

Be advised, a lot of articles say to use the diskpart "clean" command. That command erases the ENTIRE drive - ALL PARTITIONS. If you don't have a backup of what you want to keep, it will get erased using the CLEAN command.

 

Worked just fine here. Thank you

 

I'm glad it could help Burgurne. *Smile

 

Hello, I was successfully able to convert to UEFI using this tutorial. I checked my partitions and noticed that a new partition (EFI System Partition) was added. Is it safe to delete this to get more memory or should I leave it as is?

 

Hello dowon, *Smile

The EFI partition is normal. You do not want to delete it since it is required to boot a UEFI Windows installation.

I'm glad it went smoothly for you.

 

The EFI System Partition is now what the computer is booting from. Delete it and the computer will not boot.

 

Ok the conversion went well. Although it messed up System restore, there was a C drive (missing) in the available drives which had to be deleted.
Also it has assigned a drive letter E to the System reserved partition when it did not have one before.




Should the drive letter be removed?

 

Hello Kpat62, *Smile

Yes, you can remove the drive letter for "E". It normally wouldn't have one.

 

Thank you Brink
I set the label to none. All is well.

 

Not that I'm aware of. *Sad

You might create a separate thread in the Installation & Upgrade forum area to see if someone may know an easier way.

 

I have a triple-boot system: Windows 7 + Windows 10 + Linux Mint.
I have backed up everything, so can I use that method with accepting that things can go wrong?

 

Hello ntd252,

I wouldn't recommend doing this when you have a multiboot system like that. It will most likely break it. *Sad

 

Is there any way to do it quicly?
In the past, I installed Windows 7 first with a 100MB System Reserved, then Windows 10 and last Linux Mint.
Linux uses Grub2, while Windows7/10 use Windows boot manager.
I will be sad if I have to copy everything from current disk, convert it and then get data back. *Sad