Windows 10: MBR2GPT Not Working (Disk Layout validation failed for disk 1)

Hi there, I keep getting this error when trying to convert my system from MBR to GPT.

I had a system made for me (for work) and the company installed my OS in legacy mode... I have two drives, one 512gb NVME Samsung 960 EVO and one Seagate 1 TB disk drive.

I'm booting into command prompt mode (from advanced recovery options) and running the command mbr2gpt /validate /disk:1 .

I had one partition only and even shrunk it by 3 Gigs (unallocated) just to give the tool space (it worked for other users) however I ran into the same issue even after doing that.

Just another note, the 1tb drive (non os) has a System Reserve Partition of 500mb

Any suggestions?

:)

 

MBR2GPT not working


I ran mbr2gpt from elevated command prompt:
PHP Code: 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

C:\WINDOWS\system32>mbr2gpt /allowfullos /validate /disk:1
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

 

MBR2GPT Validate failed

Sir,

I appreciate your help but

It requires pro edition for the function,the conversion is not possible on the free edition.Is there any way to use the system provided
mbr2gpt tool and I wish to know why the
validation failed?

 

Unsupported disk layout for UEFI firmware

Yes. Just download the Media Creation Tool and it will let you download an ISO file for the current version of Windows 10 (version 1709, build 16299.15). You can also have the Tool directly create a bootable USB stick with version 1709 of Windows on it.
If you already have this ISO file, a utility called Rufus can be used to create a bootable USB stick (8GB minimum size thumb drive required). http://rufus.akeo.ie

The steps to fix things will be:

• first create the UEFI-bootable USB stick (it will have a FAT32 format, rather than NTFS) using Rufus or Media Creation Tool
• Restart the computer and tap F2 to enter BIOS. Switch to UEFI mode. Leave Secure Boot disabled for now if that is an option.
• Exit and it will restart with the bootable thumb drive inserted. This time try tapping F12 which usually gives a boot menu. The USB should show up in the list, if it has been created right for UEFI.
• Once Windows Setup loads the first screen, use SHIFT-F10 to get a Command Prompt window.
• Now we can try to run MBR2GPT to convert the disk.
• First, MBR2GPT can validate that conversion is possible:
  • mbr2gpt /validate
  • assuming it validates OK:
    • mbr2gpt /convert
• Type exit to return to the Windows setup screen or just close the Command Prompt window.
• Cancel Windows setup by closing the setup window and let the computer restart to your existing Windows build 10240
• Once back in Windows, your disk should now be capable of upgrading to build 1709.
• Version 1803 of Windows 10 will be released this month or in April. If you want to wait to upgrade directly to that, it would be fine to do that. Meanwhile, you are now running in UEFI mode. There is a chance that you might be auto-upgraded
  by Windows Update to version 1709 anyway, so upgrading now is fine too.
• To upgrade now, from within Windows run setup.exe from your mounted ISO file or USB stick. Do not boot from the install media to upgrade.
• You can also now tap F2 during boot to enter BIOS and enable Secure Boot