Windows 11 Upgrade - MBR to GPT Issues

I have 3 PCs in my office with existing W10 Pro installs that are all current and up to date.

The PCs all supper UEFI and Secure Boot.

They are running in UEFI mode in the bios and not Legacy and boot to W10 just fine.

When I use the FULL licensed version of Mini Partition Tool to convert the drives from MBR to GPT and reboot I got BSD and cannot get it to boot into Windows.

I have been at this for hours and tried many, many things but so far nothing works. I have already converted 2 other PCs in the office and had no issues with the conversion and then upgrade to W11.

These are the last ones and are not cooperating at all. I am at my wits end and need help from more knowledgeable people.

Before anyone jumps on me YES I have my data backed up (Macrium Reflect full drive images).

Just to recap my process has been

1 - Full drive image with Macrium Reflect

2 - Reboot using Mini Partition Tool FULL version USB rescue medie

3 - Use MPT to convert the drive from MBR to GPT

4 - Reboot gives BSD



Things I have tried

Macrium Reflect "Fix Windows Boot" option with a USB rescue drive - no help

I have gone through steps found on the 11 forums using diskpart, listdisk, etc to create the UEFI partition that is supposedly missing - no help



Not sure what else to do. At the moment I am restoring the drive image (working W10 install) so I have my working start point back.

All PCs are 1 single SSD drive with 2 separate partitions (C for Windows, D for Programs).



Any help you guys can provide would be greatly appreciated

GCS2000 said:

They are running in UEFI mode in the bios and not Legacy and boot to W10 just fine.


Any help you guys can provide would be greatly appreciated

Click to expand...

The Microsoft standard is for UEFI to install to a GPT disk. How did you end up botting in UEFI mode (not legacy) with an MBR disk? Please post a screenshot of MiniTool Partition Wizard showing the disk layouts.

NavyLCDR said:

The Microsoft standard is for UEFI to install to a GPT disk. How did you end up botting in UEFI mode (not legacy) with an MBR disk? Please post a screenshot of MiniTool Partition Wizard showing the disk layouts.

Click to expand...

Will post MPT screenshot and Bios screenshot shortly

Thanks

screenshots

Isn't the bootable USB causing the issue? Do you have it unplugged when you are trying to boot up on Windows?

badrobot said:

Isn't the bootable USB causing the issue? Do you have it unplugged when you are trying to boot up on Windows?

Click to expand...

Nope only there to boot in to MPT directly (no Windows). If I convert the drive to GPT and remove the MPT USB bootable drive I get BSD and cannot get it to boot.

PC is a Beelink Sei 12 if that even matters

You have a very unusual setup that is not officially supported by Microsoft. The standard to boot in UEFI mode is to have a GPT disk with a FAT32 EFI System Partition. The computer is booting from your C: drive. I recommend you delete the 100 mb System Reserved Partition at the beginning of the drive and try again.

The drive is still MBR and the boot loader is on C:.
As you can see on NavyLCDR drive 2 image, to boot as UEFI you need a Fat32 partition.
You can convert the drive to GPT with MiniTool and then format the first partition (system reserved) as Fat32 and install the boot manager on it. Very easy.

NavyLCDR said:

You have a very unusual setup that is not officially supported by Microsoft. The standard to boot in UEFI mode is to have a GPT disk with a FAT32 EFI System Partition. The computer is booting from your C: drive. I recommend you delete the 100 mb System Reserved Partition at the beginning of the drive and try again.

Click to expand...

so delete the System Reserved Partition, reboot (confirming it still goes to Windows 10) then convert to GPT with MPT and reboot and hope for the best?

i wouldnt delete it right away... *if it were me* - i would boot with with a partition manager, shrink the volume to create another vol of roughly 50gb in size. then delete the reserved partiton, install windows 11 on the 2nd partition, then reboot and set the proper partition as default boot. once working, then you can delete the newly installed win 11 part.

GCS2000 said:

I have been at this for hours and tried many, many things but so far nothing works. I have already converted 2 other PCs in the office and had no issues with the conversion and then upgrade to W11.....

....Just to recap my process has been

1 - Full drive image with Macrium Reflect

2 - Reboot using Mini Partition Tool FULL version USB rescue medie

3 - Use MPT to convert the drive from MBR to GPT

4 - Reboot gives BSD

Click to expand...

You might like to try the method I used to migrate a legacy/MBR install of Windows 10 from an old unsupported machine to my System One in My Computers below, a new UEFI/GPT supported one, so that it could then be upgraded to Windows 11.

First make a Macrium Reflect image of the old machine.

Next do a clean install in UEFI mode of the same version of Windows 10 on the new machine, this formats the drive as GPT and sets up all the required partitions. If it says the drive is currently MBR and it can't install, then from a command prompt use Diskpart to convert it to GPT.

Then restore JUST the C: partition from the Reflect image to replace the one created by the clean install (you can resize the partition to fit during the restore, if required).

Finally use the Reflect rescue media's 'Fix Windows boot problems' too to build the correct BCD entry. Windows should now boot.

Bree said:

You might like to try the method I used to migrate a legacy/MBR install of Windows 10 from an old unsupported machine to my System One below, a new UEFI/GPT supported one, so that it could then be upgraded to Windows 11.

First make a Macrium Reflect image of the old machine.

Next do a clean install in UEFI mode of the same version of Windows 10 on the new machine, this formats the drive as GPT and sets up all the required partitions.

Then restore JUST the C: partition from the Reflect image to replace the one created by the clean install (you can resize the partition to fit during the restore, if required).

Finally use the Reflect rescue media's 'Fix Windows boot problems' too to build the correct BCD entry. Windows should now boot.

Click to expand...

so in my case (already have the image).

1 - Wipe drive (I do not have another drive to install to)
2 - Install fresh W10 be sure it installs as GPT and not MBR
3 - Verify it boots into W10 ok
4 - Now restore old c drive from image in place of current c drive (ie this newly done W10 install)
5 - Once restored run the fix windows boot problems
6 - Boot to Windows 10
7 - Resize drive to get my d drive back on as well (specific to my case only of course)

**Key in all of this is to restore from the old image ONLY the C drive partition and not the entire drive -- correct?

How do I make sure W10 installs as GPT and not MBR?

Did you read my post #8?

- Use the MiniTool to convert the drive from MBR to GPT
- To make your drive 0 boot able, boot from a Win 10 or Win 11 installation drive and at the Windows Setup screen, press Shift+F10 simultaneously to open a command line prompt. Type:
Diskpart
list vol (take note of the windows partition letter)
sel select disk 0
select part 1
del part override
create part EFI size=100
format fs=FAT32 quick
assign letter=W
create part msr size=16
exit
bcdboot E:\Windows /s W: /f UEFI (replace E: with the windows partition letter)
exit
diskpart
select vol W
remove letter=W
exit
exit

GCS2000 said:

**Key in all of this is to restore from the old image ONLY the C drive partition and not the entire drive -- correct?

Click to expand...

correct, that's how I did it. The clean install creates the EFI partition and a Recovery partition, you just drop the old C: partition into it to replace the one from the clean install.

Megahertz said:

- Use the MiniTool to convert the drive from MBR to GPT
- To make your drive 0 boot able, boot from a Win 10 or Win 11 installation drive and at the Windows Setup screen, press Shift+F10 simultaneously to open a command line prompt. Type:
Diskpart
list vol (take note of the windows partition letter)
sel select disk 0
select part 1
del part override
create part EFI size=100
format fs=FAT32 quick
assign letter=W
create part msr size=16
exit
bcdboot E:\Windows /s W: /f UEFI (replace E: with the windows partition letter)
exit
diskpart
select vol W
remove letter=W
exit
exit

Click to expand...

This was the process I read about on this forum and have tried it and will not boot after the conversion. I used a W10 Pro USB install drive

You can also use mbr2gpt.exe

Not clear what is going on there.

Have a look with another partition manager. Diskgenius free version and post screenshot of what it says.

I always use diskgenius to do the conversion.

Then make sure the 100mb partition is set to id C12A7328-F81F-11D2-BA4B-00A0C93EC93B and populate the 100mb partition using bcdboot command.


**********************************************************

Is there any message on the bsod screen you have had so far?

GCS2000 said:

This was the process I read about on this forum and have tried it and will not boot after the conversion. I used a W10 Pro USB install drive

Click to expand...

You have first to convert the drive from MBR to GPT. If you do it right it will work.

Bree said:

correct, that's how I did it. The clean install creates the EFI partition and a Recovery partition, you just drop the old C: partition into it to replace the one from the clean install.

Click to expand...

Interesting - and it keeps all the data and doesn't cause the drive to revert to MBR? How do I make sure W10 installs to GPT and not MBR which I think is its default.

Megahertz said:

You have first to convert the drive from MBR to GPT. If you do it right it will work.

Click to expand...

Yes I converted it with MPT first, then rebooted got BSD, then rebooted with W10 install USB went to command prompt and followed the steps you listed

Bree said:

You might like to try the method I used to migrate a legacy/MBR install of Windows 10 from an old unsupported machine to my System One in My Computers below, a new UEFI/GPT supported one, so that it could then be upgraded to Windows 11.

First make a Macrium Reflect image of the old machine.

Next do a clean install in UEFI mode of the same version of Windows 10 on the new machine, this formats the drive as GPT and sets up all the required partitions. If it says the drive is currently MBR and it can't install, then from a command prompt use Diskpart to convert it to GPT.

Then restore JUST the C: partition from the Reflect image to replace the one created by the clean install (you can resize the partition to fit during the restore, if required).

Finally use the Reflect rescue media's 'Fix Windows boot problems' too to build the correct BCD entry. Windows should now boot.

Click to expand...

So far this is working out. I have the drive as GPT now with my old W10 install running as it should be. I am upgrading to W11 now and then will move my D drive back on afterwards. Let's hope all finishes up correctly and then I can get the other 2 PCs done in the same manner. Appreciate the help!