So after realising that my desktop PC has been running in BIOS mode (how 1970s and probably the result of multiple clones from HDD to 10k HDD, to 10k HDD in RAID0 to SSD and to another SSD) and with a free weekend I thought it was time to have a look at the MBR2GPT tool.
However in running the validate phase I was getting the error message:
Disk layout validation failed for disk 0
After following through a few red herrings on the internet I had a bit more of a dig into what the tool was up to and it appears that one of the first steps is to shrink the OS partition.
It appears that the fix is actually to preempt this and shrink the OS partition yourself (I reduced it by about 1GB – which made sense as one of the new partitions goes right in at the end of the disk), given these kinds of steps should only be performed by a person who knows what they are doing and understands the implications I won’t go into any detail as to how to do this other than providing the screenshot below.
Oh my lord, thank you so much – of all the fixes for the disk validation error this is the ONLY one that fixed it and allowed MBR2GPT to run properly
Thank you so much for this post! It was driving me nuts.
I wanted to pull the drive from a PC (bad power supply/motherboard-not worth repairing) and use it in a new PC.
The old PC was configured for DOS and the format was MBR. The new PC was UEFI/GPT.
First thing I did was clone the old drive to a “temp” drive to see if my idea would work. Good thing I did as while the clone worked, I couldn’t get it converted to GPT.
I tried many things: AOMEI, MBR2GPT, PartionAssist, MiniTools, but all failed. And failed BIG time, as in it wiped out the partition on the ‘temp’ drive. So, I used DiskPart to ‘clean’ the ‘temp’ drive and start again, and again. I must have tried at least 12+ times. I too got the MBR2GPT ‘validation failed’ and couldn’t figure it out. Strange as the cloned drive could be read by any system (UEFI/BIOS) in either a USB chassis, a USB dock, or via a red SATA cable.
The solution finally was to shrink the ‘test’ drive by 1G to make space at the end of the drive. Only then did the MBR2GPT /validate pass!
Once /validate passed, I tried mbg2gpt /convert allowfullos and that worked with a successful message, but it did complain about an .XML file. I rebooted into the BIOS (setup F10) and ‘enabled secure boot / disable legacy’ (HP wording) and the system booted perfectly into GPT/UEFI.
I did have 1G at the end of the partition display with a new EFI between the boot & C-drive.
So, I extended the C-drive to use that 1G I create and reclaim that space.
All is finally working perfectly! Thanks again
You fucking smart motherfucker!!! I love you! I spent hours researching this problem, 200 reboots later, I stumble across this post. I hope you don’t take it down. I’m sharing it on several of the stack pages that were of NO help. Wonderful man, thanks!