Shifting from BIOS to UEFI with the Windows 10 Creators Update MBR2GPT disk conversion tool

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Contributor

Comprehensive yet quick video overview that explains how you can safely and non-destructively convert a Windows 10 machine from legacy BIOS to UEFI disk partitioning; and how you can automate the conversion as part of your in-place upgrade process from Windows 7 to Windows 10.

 

52 Replies
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One thing I noticed when performing the conversion during an upgrade task sequence, you will lose the ability to "rollback" to previous build of Windows 10. This makes sense but I didn't see it documented anywhere.

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is it necessary to have Creators update to execute mbr2gpt command?

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It's necessary to have Creators Update if you wish to run the tool from within Windows (Full OS). MBR2GPT does support older versions of Windows 10 when ran from the WinPE thats included in Windows ADK 1703.

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I get this error when trying to do the /validate
ValidateLayout: Wrong boot partition count, expected 1 but found 0.

Any idea why that is?
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Just from the look of the error, it sounds like it cannot find a boot partition. How are you running the command?
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mbr2gpt /disk:1 /validate

I have tried from both WinPe and within Windows.

This is the full transcript for the command prompt.

C:\Windows\system32>mbr2gpt /disk:1 /validate /allowfullos /logs:c:\temp
MBR2GPT: Attempting to validate disk 1
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Disk layout validation failed for disk 1
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Is there a reason your validating against disk 1? Try this:
mbr2gpt /disk:0 /validate
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My OS is intalled on Disk 1
So if I run is on disk:0 then I get this error instead.

C:\Windows\system32>mbr2gpt /allowfullos /validate /disk:0
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Cannot find OS partition(s) for disk 0
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hi 

i tried to convert from mbr to gpt using the cmd 

my widows builed is 1703 

when i enterd the command to validate the disk 

this is the message that i got

can you please help me to know what is wrong

my laptop allow for uefi

 

C:\Windows\system32>mbr2gpt /validate /disk:0 /allowfullos
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Disk layout validation failed for disk 0

 

thanks in advanced

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Error while validating Disk

C:\WINDOWS\system32>mbr2gpt /allowFullOS /validate
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Disk layout validation failed for disk 0

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Hello, I also get this error: Cannot find OS partition(s) for disk 0.

The OS is installed on Disk0. Did you find a fix?

 

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hi, if mbr disk have 4 partitions it will fail, i deleted one partition then it worked.
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Does this work for Home or Pro versions of Windows 10? Or just enterprise?

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Check your setupact.log & setuperr.log files in %Windir%\Panther. There should be some verbose information in one of those logs.

-Mike

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found any solution?
same error here stuck with it
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Trying OS is intalled on Disk 0
only have 3 drives left remove one already 

now C: OS, D:Data , F: System Reserved
 Still getting this error

please help

 

C:\Windows\system32>mbr2gpt /allowfullos /validate /disk:0

MBR2GPT: Attempting to validate disk 0

MBR2GPT: Retrieving layout of disk

MBR2GPT: Validating layout, disk sector size is: 512 bytes Cannot find OS partition(s) for disk 0 

I accidentally deleted the MSR partition from the drive when downloading Windows. Should I recreate the MSR? If so, does anyone know how to do it?