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Zachary-Cavanell's avatar
Zachary-Cavanell
Bronze Contributor
Apr 05, 2017

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

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 con...
windows 10
ftrout's avatar
ftrout
Brass Contributor
Apr 09, 2017
Just from the look of the error, it sounds like it cannot find a boot partition. How are you running the command?
Lasse Gaardsholt's avatar
Lasse Gaardsholt
Copper Contributor
Apr 09, 2017
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
  • Dhruv Joshi's avatar
    Dhruv Joshi
    Copper Contributor
    Aug 23, 2018
    How many partitions do you have ?
  • Dhruv Joshi's avatar
    Dhruv Joshi
    Copper Contributor
    Aug 23, 2018

    This is happening because you have more than 3 partitions on your disk 0 or disk 1 where you have the windows 10 installed. Or probably you have selected wrong disk. try on disk 0.

  • William A. Paternina M.'s avatar
    William A. Paternina M.
    Copper Contributor
    Aug 14, 2018
    I Had the same error while trying to convert my mbr hard disk to gpt.
    what I did for getting success was the following:
    1.- checking my partitions in computer management, I saw my two partitions (system reserved and OS ) were primary partitions, but data partition Or D: (as I use to call it) was in logical partition state.
    2.- I installed Minitool Partition Wizard and converted logical partition to primary.
    3.- Run into windows Enviroment the mbr2gpt /convert /disk:"number of the disk" /allowFullOS and the... IT WORKED!

    Hope you Found this helpful.
  • Roman Hauzar's avatar
    Roman Hauzar
    Copper Contributor
    Apr 06, 2018

    I had some error..  I tried this mbr2gpt /validate /disk:1 /allowFullOS /logs:c:\temp\Errors 

      Error make sense, Msg="ValidateLayout: Too many MBR partitions found, no room to create EFI system partition." 

     

      4 primary and no extended is valid for MBR, but tool probably need space to create 1 new partition before conversion.

      other problem was not existence of Recovery partition - i just copied it from Windows 7 Efi instalation, is mostly just empty space - to backup image is few MB big.

  • ftrout's avatar
    ftrout
    Brass Contributor
    Apr 09, 2017
    Is there a reason your validating against disk 1? Try this:
    mbr2gpt /disk:0 /validate
    • Lasse Gaardsholt's avatar
      Lasse Gaardsholt
      Copper Contributor
      Apr 09, 2017

      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
      • Khushal Patel's avatar
        Khushal Patel
        Copper Contributor
        Apr 16, 2017
        found any solution?
        same error here stuck with it

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