Forum Discussion

Aaron B's avatar
Aaron B
Copper Contributor
Mar 23, 2018

MBR2GPT Disk layout validation failed

When i try to run    mbr2gpt /validate /disk:0 /allowFullOS   i get the following output   MBR2GPT: Attempting to validate disk 0 MBR2GPT: Retrieving layout of disk MBR2GPT: Validating ...
Palani Samy's avatar
Palani Samy
Copper Contributor
Jul 21, 2021

I was facing similar problem as my disk partition was in MBR format but I need it to be GPT format.
Disk validation failed.
Easiest way is solve this problem is as given below.
Go to Disk Manager -> Select disk (0 or 1 ) you want convert and select the partition eg. C -Drive
Right click --> Shrink the disk and put shrink value to 200MB ->OK
Go to CMD with admin mode run the below command
mbr2gpt /validate /disk:0 /allowFullOS -> Enter
Validation is success
Run below command to convert
mbr2gpt /convert /disk:0 /allowFullOS
Disk will be converted to GPT
Go to BIOS and change Legacy to UEFI mode and change boot sequence
Your system will boot with mfg logo
NO Data loss
allansplace's avatar
allansplace
Copper Contributor
May 19, 2024

Palani Samy I know this post was long ago.  I'm having trouble with this.  I'm really hoping someone out there can help out!  

Background: Windows 10 Pro, use it as web server, need it working and online!  Something happened, and it would not boot.  Sabotage by someone out there wanting Bitcoin money.  After hours of trying to diagnose, I used EasyRE Professional, and it worked.  The system boots.

Now, however, I cannot make any backup (clone using Clonezilla).  Clonezilla's error message states,

"The disk contains mismatched GPT and MBR partition: /dev/nvme0n1",

"It will confuse Clonezilla and might make the saved image useless or fail to close the disk."

and

"The directory for this inputted image name does NOT exist: /tmp/ocs_onthefly_scr.Pw91VG/d2d-pseudo"

etc.  I know this is not a Clonezilla forum.  But it seems to me that my system now boots form MBR and not GPT as it has always done previously. 

In using MBR2GPT, I get the same error, "Disk layout validation failed for disk 0".

Maybe long-winded, but a little background. 

Now the question - your advice states to shrink the drive c: to 200MB.  But my entire OS, with website and everything else, is 141GB of 237GB.  How could this be shrunk to 200MB?

I'll spend two weeks rebuilding my server if I screw this up, and I now have NO clone as a backup.

Hope someone can help!  Thanks! -Allan