Help needed converting MBR to GPT

[Oifish]

I recently upgraded my rig and everything has been working great. I'd like to fully utilize the 32Gb M.2 Optane card I purchased. However this requires the boot drive to be in GPT format opposed to MBR.

I cloned my existing 320Gb HDD over the to the 500Gb SSD, and it boots just fine. After doing some research I found that I could use GPTGEN to convert the drive without losing my data. After doing the conversion, I am now unable to boot from the SSD (even after changing the bios from AHCI to UEFI.

I have a feeling that the SSD hasn't been partitioned correctly, but I'm having a hard time finding the correct information on this. Any assistance would be fantastic.

 

[UsandThem]

Try this guide that traderjay posted:

https://forums.anandtech.com/thread...grading-hdd-from-sata-to-nvme-solved.2529661/

 

[Oifish]

Hmm I tried this, but got the error:
Disk layout validation failed

I'm going to try from the Windows PRE (rather than using the /allowFullOS option) to see if that changes anything.

Also I may create an 128mb EFI partition prior to attempting the conversion if the above doesn't work.

Anything else I should try?

 

[Oifish]

Got it! I had to open some space at the end of the drive to allow MBR2GPT to create the EFI partition.

 

[XavierMace]

https://social.technet.microsoft.co...erting-windows-bios-installation-to-uefi.aspx

I've used that guide successfully before, using Disk Management to do the initial conversion.