Forum Discussion

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

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

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.