Please run these commands from admin Command Prompt:
bcdboot C:\Windows /s C: /f BIOS
mbr2gpt.exe /validate /disk:0 /allowfullos
Post the output here.
Need to convert MBR into GPT to enable UEFI boot and secure boot. But MBR2GPT cannot find OS partition
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Radek
20
Reputation points
I run MBR2GPT in full OS mode and also from instalation media, still with the same result : "MBR2GPT cannot find os partition".
I have currently enabled legacy bios, see system info:
See printscreen from disc manager:
Primary partition seems ok to me, it contain boot record and is active...
Windows for home | Windows 10 | Settings
Accepted answer
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Ramesh Srinivasan 164.5K Reputation points Volunteer Moderator2025-07-27T15:24:22.42+00:00 -
Radek 20 Reputation points
2025-08-02T10:22:56.1866667+00:00 This worked. mbrgpt validation suucessfull now. Many thanks!
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Ramesh Srinivasan 164.5K Reputation points Volunteer Moderator
2025-08-02T12:23:06.34+00:00 You're welcome!
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1 additional answer
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Neil D 27,975 Reputation points Volunteer Moderator2025-07-27T13:58:16.97+00:00 The disk does seem to be missing some windows partitions, whether that is the reason I don't know.
Have you read through all the instructions to use MBR2GPT.
EaseUS offers another way to change the system partition. Make sure the bios is capable of using UEFI and Secure boot before you start.
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Radek 20 Reputation points
2025-07-27T14:12:36.44+00:00 Thanks for the suggested solution. However I need only this single task to be solved and paying USD 30+ for this seems a bit too much.
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Neil D 27,975 Reputation points Volunteer Moderator
2025-07-27T14:38:11.7366667+00:00 It shows the software as free. Are you saying when you try to use it there is a charge?
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Neil D 27,975 Reputation points Volunteer Moderator
2025-07-27T14:45:57.62+00:00 In addition:
The software installs for me and I can select the option for Disk Converter then MBR=>GPT. Is it asking for payment after that.
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Radek 20 Reputation points
2025-08-02T10:23:52.3333333+00:00 yes, installation was free, but the function MBR 2 GPT is paid, unfortunately
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