Convert a Windows 10 installation from Master Boot Record (MBR) to GUID Partition Table (GPT)

[spoitras]

This may be of some interest to folks with a legacy boot windows 10 installation. There is a utility included in the newest windows 10 version (creator's) that converts a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) rather painlessly. It's called mbr2gpt.exe and you can find its documentation here: https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

Here's what I did to convert my disk.

Check the boot loader with validate:
MBR2GPT.EXE /disk:0 /validate /allowFullOS

If the results are no errors, convert:
MBR2GPT.EXE /disk:0 /convert /allowFullOS

Afterwards, you need to disable CSM in your BIOS.

P.S. Make sure you're using the right disk number (use diskpart and the "list disk" command to find the right one).

 

[MrNarrow]

This may be of some interest to folks with a legacy boot windows 10 installation. There is a utility included in the newest windows 10 version (creator's) that converts a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) rather painlessly. It's called mbr2gpt.exe and you can find its documentation here: https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

Here's what I did to convert my disk.

Check the boot loader with validate:
MBR2GPT.EXE /disk:0 /validate /allowFullOS

If the results are no errors, convert:
MBR2GPT.EXE /disk:0 /convert /allowFullOS

Afterwards, you need to disable CSM in your BIOS.

P.S. Make sure you're using the right disk number (use diskpart and the "list disk" command to find the right one).

Hello!

I too discovered this today and am interested in using it to convert my legacy Windows install (MBR v1607) to GPT.

However, the reason I want to do the conversion is to allow me to install the latest Windows update (v1703) as currently I am getting an error saying that my 'disk layout is unsupported' when I attempt to install the update and I believe this is due to my MBR install. So I need the tool before I can install the update, but it is this update that includes the tool

How did you go about running the MBR2GPT tool, did you succeed in installing the latest version of Windows (v1703) with MBR first?

Cheers.

 

[MrNarrow]

This may be of some interest to folks with a legacy boot windows 10 installation. There is a utility included in the newest windows 10 version (creator's) that converts a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) rather painlessly. It's called mbr2gpt.exe and you can find its documentation here: https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

Here's what I did to convert my disk.

Check the boot loader with validate:
MBR2GPT.EXE /disk:0 /validate /allowFullOS

If the results are no errors, convert:
MBR2GPT.EXE /disk:0 /convert /allowFullOS

Afterwards, you need to disable CSM in your BIOS.

P.S. Make sure you're using the right disk number (use diskpart and the "list disk" command to find the right one).

Got it working!

I backed up my Windows install and spent the day messing around with this trying to convert MBR to GPT to no avail so I decided the restore the backup I made in defeat.

However after the restoration I booted into Windows and the update installed with no issues which then allowed me to use the MBR2GPT tool to do the conversion! not sure how this happened apart from adding the 'Microsoft' EFI folder to my EFI partition as everything else I did today was reverted by the restoration...

 

[Bob_the_Tomato]

I did this last week. In my case I had to remove the old EFI partition before the program would complete successfully.