Convert MBR to GPT without losing data

[ranchhand]

@ ProWo: yes, I know, this whole mess is Alice in Cyberland.
@ The_Doman: Pic below. As ProWo said, suddenly one disk disappears. (Twilight Zone music starts here). See below, and C: is marked as boot.

[Attachment 86899 - Click to enlarge]

[ranchhand]

Afterthought.....I just now booted from my thumb drive and used MBR2GPT to validate both partition 0 and partition 1, both failed.

[ProWo]

Afterthought.....I just now booted from my thumb drive and used MBR2GPT to validate both partition 0 and partition 1, both failed.

You must use mbr2gpt on disk 0, not on the partitions.
Type mbr2gpt /h or mbr2gpt /? for help on the exact syntax.

Read
https://www.windowscentral.com/how-convert-mbr-disk-gpt-move-bios-uefi-windows-10

[krykmoon]

Thanks to both! Yes, I noticed that Disk Genius has a cloudy reputation.
OK, well, so I created a bootable thumb drive (using Rufus) with an ISO of Microsoft's MBR2GPT, and booted it. Same thing, it cannot find the OS on my drive. I have attached a picture of the result. I tried targeting both Drive0 and Drive1, and it will not validate. I always get the same result with whatever tool I try. Really strange...my drive is working perfectly, in years never had a problem. There must be something that is side-tracking the access.
Just a thought....I read recently on one website that conversion needs three partitions, and I have only two. Anyone heard anything about that?

[Attachment 86892 - Click to enlarge]

I noticed it only now, but the second MBR2GPT command is mistyped : after the word "disk" there's directly the drive number without the (needed) colon before.. As a matter of fact if you see the messages after the operation MBR2GPT retried to validate disk 0 again, not disk 1.

Don't know if this could be related to your problems or not (probably not XD ), but since I noticed it I thought it was worth reporting it to you.

[ranchhand]

Thanks Krykmoon....yes, I attempted targeting 0 as well as 1. I just keep getting the same error message, "can't find the operating system".
and...yes I did make the ":" mistake you mentioned, and it made no difference inserting it.

My wife is running a new computer I made for her. I installed a new NVme drive and formatted using GPT instead of MBR. I re-imaged her W10 back onto it. Went super smooth and computer booted and ran great. About a month ago I went in, activated GPT and on the first reboot it instantly converted to W11 in about 25 seconds. It's running great with no program or data loss.
I think I am going to have to get radical here.
Thinking of wiping my drive, change to GPT, and imaging my wife's W11 OS onto the drive. Then I will change the Windows key number from hers to mine. Maybe should work? I dunno, but I am making no progress over several days and lots of suggestions not only from this website but another (Bleeping Computer).

I checked my Windows key M/Soft website...far as I can discern, it is active and legal. I'd feel better actually talking to a person but that isn't going to happen.

I wonder....when I image (using Macrium Reflect) her drive onto mine, will that change my SSD format to GPT or does an imaging not touch the disk format??

[The_Doman]

@ ProWo: yes, I know, this whole mess is Alice in Cyberland.
@ The_Doman: Pic below. As ProWo said, suddenly one disk disappears. (Twilight Zone music starts here). See below, and C: is marked as boot.

[Attachment 86899 - Click to enlarge]

And it does not bother/concern you when suddenly you miss a complete HDD/SSD disk (and a DVD unit?) in your system?
I would first investigate this further before you are doing any conversion operation attempts?
Possible physically disconnect extra disks you find connected, loose wire/connectors?

The disk management shows a basic/simple disk layout with the boot and system files on the same partition.
This makes it possible easy to reset the BCD/boot configuration.

[The_Doman]

Thinking of wiping my drive, change to GPT, and imaging my wife's W11 OS onto the drive. Then I will change the Windows key number from hers to mine. Maybe should work? I dunno, but I am making no progress over several days and lots of suggestions not only from this website but another (Bleeping Computer).

I checked my Windows key M/Soft website...far as I can discern, it is active and legal. I'd feel better actually talking to a person but that isn't going to happen.

I wonder....when I image (using Macrium Reflect) her drive onto mine, will that change my SSD format to GPT or does an imaging not touch the disk format??

If you already using Macrium Reflect, why not make a backup of your current system too?

If you restore a full drive backup image from another system on your PC, the disk will be restored with the same partition layout as from the image backup.
Also if the Windows versions are the same (Pro or Home), the system will reactivate again too.
Activation is linked to the hardware of your motherboard:
TenForums: Win10 Pro - Digital Activiation - Not Linked to MS Account
But even if that somehow does not work, there are options available to still re-activate Windows.

But if you are planning to use this "nuclear" option, you also could try this following procedure to reset the boot/bcd info?
Possible this can clean up all the problems from the MBR2GPT tool?
Use this procedure by booting from your bootable Windows 10/11 USB, choose repair computer/troubleshoot/command prompt.
You can also do this from the Hiren's BootCD PE
Having a Windows USB available is always advised still, so you can try a startup repair also if needed.
You can not do this from your live Windows system!!
Make sure you not have any other disk connected/active which can confuse things!
Also no guarantees or responsibility of possible data loss or unbootable system!

This procedure will delete the current boot/BCD configuration file en rebuild it from scratch.
This BCD file should be on your default C: drive, if not you should check other drive letters.
You notice the first time the bootrec /rebuildbcd command does not find any Windows installations.
Possible your situation shows different, i don't know.
After the BCD configuration is deleted,the bootrec command should be able to find and add a new clean Windows installation entry

bootrec /rebuildbcd

[Attachment 86924 - Click to enlarge]

When all is completed you should reboot and check if you still can boot the system normally.
Then you can try the MBR2GPT again to see if it accepts the new , cleaned up, boot/configuration.
Again, it is advised to run MBR2GPT from the Windows USB command line (troubleshoot/repair) or Hiren's BootCD PE

MBR2GPT

[Attachment 86925 - Click to enlarge]

[krykmoon]

Then, before deleting the BCD configuration, he could try also:

bootrec /ScanOS

bootrec /FixMBR

bootrec /FixBoot


Doing it on the right disk.
By the way... it's ALWAYS preferable to physically disconnect any other drive while doing this kind of potentially destructive operations.

[ProWo]

The easiest way should be an inplace upgrade.
I think that the mbr2gpt conversion is done by Windows itself during this upgrade.
So if you can still boot into your Windows 10, try the following:
Download a Windows 11 ISO with the latest updates
(En-Us x64 Muti Edition 24h2.26100.3915)
here
https://t1p.de/5ao6h

1) Boot your Windows 10
2) Search for the Windows 11 ISO and double-click it.
It will be mounted automatically and you will see a new drive (e.g. G:].
Switch to G:, double-click Setup.exe and follow the instructions.
If the setup fails to meet the hardware requirements, cancel the installation.
Then open a cmd console as administrator, switch to the Windows 11 ISO with G: and enter there:

setup.exe /product server

and press Enter. The installation process will restart, but this time no compatibility check will be performed.
When you get the message that Windows 11 can be installed with all your apps and settings, click Next.
If not, your Windows 10 installation is not in English. In this case, cancel and get an ISO in your installation language (this does not have to be the display language).
3) Wait until the installation is finished. If everything goes well, you have a new WIndows 11 installation, already activated.

[The_Doman]

The easiest way should be an inplace upgrade.
I think that the mbr2gpt conversion is done by Windows itself during this upgrade.

A Windows 11 in place/upgrade will NOT change the disk/partition layout!
If you (force) the upgrade, for example using the product /server bypass option, it will keep the existing disk/partition scheme.
It would be really bad if it would automatically try to convert the disk, possible resulting in systems not booting anymore.
Windows 11 will run fine on MBR/Legacy systems, just it won't allow you to install/upgrade without the "workarounds".
I tested all those scenarios extensively here on (very) old and newer hardware systems.

Download a Windows 11 ISO with the latest updates
(En-Us x64 Muti Edition 24h2.26100.3915)
here

I would advise using the official ISO/language versions for your region to keep things clear.

[ProWo]

A Windows 11 in place/upgrade will NOT change the disk/partition layout!

You are right.

I would advise using the official ISO/language versions for your region to keep things clear.

Offficial ISO/language versions cames without updates, so you'll get 24h2.26100.1.
Then you have to make several large updates afterwards.