Windows 10: GPT conversion fail, Windows OS now unrecognized and can not boot windows

I was turning on TPM 2.0 and Secure Boot when I realized I needed to convert my drive to GPT to Disable CSM and when I was in the command prompt I validated GPT successfully but then when I moved on to Convert disk to GPT it said conversion had failed so I decided to restart my pc and try again but then a black screen came up saying boot drive not found or boot drive os not found. I've tried making the boot bios legacy again and turning on csm again but it had not worked. please help!

:)

 

MBR to GPT conversion for boot disk - failing

Here's the screen shots before and after:

 

MBR to GPT conversion for boot disk - failing

Hello

Ive recently purchased a 16Gb optane memory module for my PC. Unfortunately to get it to run for me I need all my drives converting to GPT.

This was straight forward for my 500Gb data drive however it has proven to be more difficult for my boot drive.

As my current 120Gb boot drive was almost full, i took the opportunity to get a bigger 9250Gb) drive as i assumed I could set this a GPT from the off.

However, following guidance on this site: How to Clone MBR Disk to GPT Disk/SSD - EaseUS
I saw i needed to set my new 250gb drive up as MBR, and then clone my 120Gb boot to this disk before converting from MBR to GPT.

To do the conversion I followed command prompt> mbr2gpt /convert/ allowfullos process as outlined here:
How to convert MBR to GPT drive to switch BIOS to UEFI on Windows 10 | Windows Central

Unfortunately I get the following error after the conversion has failed:

MBR2GPT: Attempting to convert disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
MBR2GPT: Trying to shrink the OS partition
Cannot find room for the EFI system partition.
MBR2GPT: Conversion failed

C:\WINDOWS\system32>

Similarly Ive tried this with my original 120Gb boot disc seeing as ive got a clone and I get the same error message.

Can anyone help?

FYi im running W10 build 18363

 

MBR to GPT conversion for boot disk - failing

From the screen shot above. Partition 2 should be EFI System partition. Somehow the script failed to create it. I just tried with my scratch disk and here's the result: