Advice to convert MBR to GPT and install Windows 11 Pro on unsupported PC

Topic

I need advice for the following mission.

I have a Lenovo M73 tiny PC. With Windows 10 Pro. I want to try and install Windows 11 Pro on it but of course it does not support Microsoft requirements : TPM 2.0 and compatible Intel processor, etc.

The drive (SSD, 500 G) was partitioned under MBR scheme, not GPT.

The M73 does support UEFI, but is not configured as such right now.

I only have 3 partitions on the drive, including a logical one for Data (I’ve had a few problems with that PC and after reinstalling Windows a couple of times I don’t have a recovery partition anymore).

So, to install Windows 11 Pro 23H2 and eventually 24H2, I need first to convert the drive to GPT and change the Bios to UEFI. Preferably without losing the Data. I’m thinking of using MBR2GPT for the conversion.

Then I would like to use Rufus to upgrade to W11 23H2, preferably without losing programs and data.

I would prefer to keep the logical partition for DATA, but if it’s too complicated, I could delete it and expand the C: partition.

Any advice on how I should proceed ?

Replies

First, make an image backup to an external disk and a backup recovery USB.

Can you post a screenshot (save as PNG and attach here) of the disk from Disk Management? We need to know if your disk is setup correctly.

MBR2GPT is the correct method, after you have a backup.

cheers, Paul

Thanks Paul,

I made a system image with Macrium. And here’s the PNG file you requested. .

I also made recovery media with Macrium. One on a DVD-RW and one on USB key. Since I don’t have a recovery partition, I chose the option shown in the attached Capture2 file.

So any advice is appreciated. Thanks.

 

 

For Windows to boot in UEFI it needs a small boot partition, which you don’t have.
I don’t know if the conversion program will create the boot partition, but you can run it and see what it does. (Use the “mbr2gpt /validate” command to test.)

cheers, Paul

Hi Paul T,

I found an exhaustive explanation on how to use mbr2gpt. I’m tempted to try it. But also hesitant to go for it. If I choke, would it be easier if I made a clean install (with Rufus) instead of an upgrade ? Lots of programs to reinstall but doable, plus I have backups of my Firefox and Thuderbid profiles.

Thanks for your help.

 

Doing the conversion won’t break anything, but then converting your BIOS to UEFI may be an issue, especially if the correct disk drivers aren’t available. This is why you make an image.

Run the validate command and let us know what it says.

If the change doesn’t work you have the option of restoring to MBR or installing afresh in UEFI.
As the PC doesn’t meet the specs it might be easier to reinstall via Rufus.

You can mount an image backup to restore specific data if required, or use your other backups.

cheers, Paul

According to what I read on the site Learn.Microsoft.com, mbr2gpt won’t validate the operation if there’s a logical partition on the drive. So I need to delete that partition first and therefore wipe out all my files (I have several backups). I’m going to try tomorrow. If it works, I’m thinking of installing W11 24h2 to avoid having to go through another installation in just a few months. Wish me luck.

Macrium Provides a way as well.

Convert an MBR disk to a GPT disk

I would lose everything then, and I’m trying to avoid that. But if everything else fails, I’ll take a look at that option. Thanks.

Well spotted, I missed the logical partition.

According to Macrium you can restore that partition and change the type to Primary.
As you already have an image it should be simple.

cheers, Paul

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Andy M, PL1

I actually used Acronis to convert my Win7 machines to GPT when I upgraded to Win10.
I found these simple instructions from the forum.

https://forum.acronis.com/forum/acronis-disk-director-forum/converting-mbr-gpt-os-already-installed

While there is no 1-step MBR to GPT conversion option for your case, you can still apply the alternative solution that you have described. Steps would be as follows:

1) boot the computer from Acronis bootable media, start Acronis True Image

2) click on Tools & Utilities tab, then on “Add new disk”

3) select your system disk and proceed, intitializing it as GPT. Upon initialization everything on that disk will be deleted, disk will become emtpy with only “Unallocated space” on it. You do not need to create any partition manually.

4) click on “Recovery” tab in bootable media and restore your system from backup to the cleaned system GPT disk.

See http://www.acronis.com/en-us/support/documentation/ATI2016/index.html#26852.html for more details.

Regards,

Slava

Interesting ! I just might try this if I can get my hands on Acronis. Thanks !

Andy M wrote:

Interesting ! I just might try this if I can get my hands on Acronis. Thanks !

It’s pretty much the same method for Macrium. You make a backup, convert the drive to GPT, and then manually drag the partitions from the backup to the blank area of the GPT drive.

https://reflect.macrium.com/help/v5/how_to/conversions/convert_an_mbr_disk_to_a_gpt_disk.htm

ETA: Also, don’t forget, your MB has to support UEFI and it has to be setup for UEFI when you make the change.

“your MB has to support UEFI and it has to be setup for UEFI when you make the change.”

To be clear : before I make the conversion ?

Andy M wrote:

“your MB has to support UEFI and it has to be setup for UEFI when you make the change.”

To be clear : before I make the conversion ?

A̶f̶t̶e̶r̶ y̶o̶u̶ c̶h̶a̶n̶g̶e̶ t̶h̶e̶ d̶r̶i̶v̶e̶ t̶o̶ G̶P̶T̶, y̶o̶u̶ n̶e̶e̶d̶ t̶o̶ r̶e̶b̶o̶o̶t̶ i̶n̶t̶o̶ y̶o̶u̶r̶ B̶I̶O̶S̶ a̶n̶d̶ m̶a̶k̶e̶ t̶h̶e̶ c̶h̶a̶n̶g̶e̶ t̶o̶ U̶E̶F̶I̶. Select the option of Legacy and UEFI before making the change. Then when you restart, you will be booting off of the recovery boot disk. (USB, DVD or CD) Then recover your disk and you should be good to go.

I’ll be honest with you, I’m a noob. So just to be sure : I convert the drive to GPT. I reboot into the bios, change the booting to UEFI, connect the Macrium rescue USB, reboot off the USB, restore the image to the SSD, and hope for the best.

Andy M wrote:

To be clear : before I make the conversion ?

If you have an option for Legacy and UEFI, that would work best. And you could change to that before you make the change to GPT.

I’ll check tomorrow. It’s almost midnight in Montreal. Thank you so much for your help. I’m going to try one of these conversion methods (with mbr2gpt or macrium) this weekend. And I’ll get back here to tell you how it went.

Andy M wrote:

I’ll be honest with you, I’m a noob. So just to be sure : I convert the drive to GPT. I reboot into the bios, change the booting to UEFI, connect the Macrium rescue USB, reboot off the USB, restore the image to the SSD, and hope for the best.

I updated the instructions. Before you start, you need to go into the BIOS and change to the setting “UEFI” AND “LEGACY”. Then follow the directions at Macrium. Don’t just restore the image. You have to drag the partitions to the correct locations as shown in the example. Then continue.

https://reflect.macrium.com/help/v5/how_to/conversions/convert_an_mbr_disk_to_a_gpt_disk.htm

I just checked the bios again. As you can see, the system tries first in legacy and then in UEFI. So I just have to change that sequence. See the picture below. Should I disable CSM and change Boot Mode (Auto) and Quick Boot ?

Andy M wrote:

I just checked the bios again. As you can see, the system tries first in legacy and the in UEFI. So I just have to change that sequence. See the picture :

Perfect!

Understood. I have to drag the partitions to the right of EFI partition or whatever it’s called. Merci !

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PL1

Andy M wrote:

Should I disable CSM and change Boot Mode (Auto) and Quick Boot ?

I would leave it. “Compatibility Support Module (CSM), a feature in UEFI firmware that allows older, legacy BIOS-based operating systems and hardware to boot, essentially emulating a BIOS environment.” Your settings look good. If you have trouble booting after the restore, you could try other settings. But it looks like your setup accepts BIOS and UEFI already.

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Andy M

Great. Wish me good luck. I’ll get back to you once it’s done (this weekend) or if I get stuck during the operation. Really appreciate your patience. Ciao !

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PL1

Signing Off!

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Andy M

I would test booting in UEFI before restoring anything. It might just work, or give you a meaningful error message.

cheers, Paul

At which point exactly during the conversion sequence ?

Suggest you take a look at Microsoft’s “official” MBR2GPT instructions and post #2454774 over in the Secure Boot thread.

I used the procedures mentioned in that post to convert my OS drive from MBR to GPT and experienced absolutely no problems.

As long as mbr2gpt.exe /validate /allowFullOS returns “Validation completed successfully“, the conversion will work.

Some important points.

Make a full image backup before doing anything!

mbr2gpt can do the conversion without losing any data so none of the existing partitions need to be erase.

The conversion process should be run from Recovery Mode so the OS is not active allowing it can make all the necessary changes to support UEFI.

If it doesn’t already exist, the conversion process will create a UEFI partition (my MBR drive didn’t have one, afterward it did.)

The UEFI partition does not need to be the first partition (as the below image shows, mine was created as partition #2)

Do not chance the BIOS setting to UEFI boot mode before hand, wait until the conversion is complete and change it during the reboot sequence.

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Andy M, Paul T

Thanks nOads. I had checked the official Microsoft instructions for mbr2gpt and it says, among other prerequisites, that “mbr2gpt won’t validate the operation if there’s a logical partition on the drive”. I have a logical partition on my drive but could delete it if necessary. I’m still looking at different methods to convert the drive. I’ll be back here with the results.

 

Bearing in mind doing so will not actually change anything on your drive, as others have suggested, you should run mbr2gpt.exe /validate /allowFullOS to see what result you get.

Regardless of what Microsoft’s instructions may say, if it displays “Validation completed successfully“, it will work and you won’t need to find another method.

 

Moderator Edit: to remove HTML

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Andy M

I did, but it failed, probably because I have a logical partition on the drive. So I’m going to try something else and if it fails, I’ll delete the logical partition and try mbr2gpt. I’ll keep you posted.

 

Andy M wrote:

I only have 3 partitions on the drive, including a logical one for Data (I’ve had a few problems with that PC and after reinstalling Windows a couple of times I don’t have a recovery partition anymore).

Bearing in mind:

The whole reason logical drives were created in the first place was to allow MBR disks to have more than 4 partitions (GPT can have up to 128.)

The fact it appears your drive never had more than 4 partitions (current 3 + recovery.)

Windows treats a logical drive D: and a simple volume D: exactly the same (i.e. like separate drives.)

You didn’t really need to create a logical drive D:, you could have created a simple volume D: instead and achieved the same results to hold your data.

With all that said, the simplest way to deal with your existing logical drive/partition to allow the use of mbr2gpt while keeping all the data it contains is:

1- Make a full backup of logical D:

2- Delete the logical partition

3- Create a new simple volume and assign it drive letter D:

4- Restore the backup to the new volume D:

Now when you run mbr2gpt.exe /validate /allowFullOS the result should be “Validation completed successfully” and you can start the conversion process.

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Andy M

That’s moving 240 GB vs. one click in MiniTool Partition Wizard.

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Andy M

Volume Z !
I downloaded the free version of MiniTool and converted the logical drive to a primary partition with a letter. Then I tested again mbr2gpt /validate and the validation was successful. Now I’m making a new Macrium Image of the entire drive just in case and then I’ll proceed with the conversion to GPT with mbr2gpt.

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Volume Z

nOads, thanks, I might try that, although the poster Volume Z suggests using MiniTool Partition Wizard to do that without losing the data. I have to check that out first.

Volume Z !
I downloaded the free version of MiniTool and converted the logical partition to a primary one with an assigned letter. Then I used mbr2gpt /validate and the validation was successful. Now I’m making another full Macrium image of the system just in case, and then I’ll proceed to the conversion with MBR2GPT.
So far so good ! Thanks !

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satrow, Volume Z

I’ve used the free version of MiniTool Partition Wizard before but, since it’s functionality is very limited vs the paid version, didn’t realize it could do that.

Glad to find out it can!

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satrow, Volume Z, Andy M

See my reply to Volume Z : it’s already done and it worked. And mbr2gpt validation was successful. I will be able to make the conversion. Thanks.

Guys !

I’m glad to report the conversion worked ! I rebooted in the Bios, changed the priority to UEFI, and rebooted again, no glitch. Only thing, there was a message in the MBR2GPT report to the effect that it had failed to update ReAgent.xml and that I should try to do it manually. Should I do something about that, knowing there was no recovery partition on my drive anyway ?

I opened a Commend Prompt and reagentc was enabled. I disabled and then enabled it again. The operation was successful. So I guess everything is fine. Except, if you look at the first partition of my drive, it’s a basic data partition. Is that normal ?

Thanks to n0ads, Volume Z and PL1 for your help. Really appreciate it. Here’s a capture of the drive now :

 

All partitions should be Simple on a PC. Anything else is server / playing territory.

cheers, Paul

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Andy M

I was just wondering why it’s called a data partition and what is the purpose of that partition. Anyway, thanks, the conversion went well thanks to everybody here. Next step, in a few days, I’ll try to install windows 11. Still not sure if I should go straight for 24h2 so I would not have to reinstall again in November, or if I should start with 23h2.

The term “data” is a convenient label meaning “any use”.

cheers, Paul

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Andy M

Andy M wrote:

Except, if you look at the first partition of my drive, it’s a basic data partition.

If you go back and look at the image of your drive setup in your post #2760094 and compare it to the new setup you’ll see the only difference is partition 1 (SYSTEM_DRV) shrank to 1.37GB and there’s now a 100MB partition between it and partition 3 (Tiny C:).

That’s the new EFI partition mbr2gpt created and I believe what’s confusing you is, in the section “above” the graphic presentation, it’s the first item in the list.

However, that doesn’t mean it’s partition 1, it’s listed first simply because, by default, the “Volume” column is sorted alphabetically.

In fact, notice how it’s labeled Disque 0 partition 2 not partition 1!

BTW, glad we were able to help you get it squared away.

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Andy M

Understood. I’m far from being an expert, so at first I was a bit overwhelmed by the numerous approaches suggested, but in fine, each advice made it clearer and clearer. So thanks again everybody. Merci from Montreal !

The conversion from mbr to gpt worked. Next step, installing windows 11 on the unsupported PC. So Out and over for now. Thanks all.