Boot from a USB stick like you are going to install windows

Open the CMD window

Run the following command:

  • diskpart
  • list disk

This will give you a list of partitions to choose from.  Take not of the one that does NOT have a * in the GPT table and is your C drive

Then run this command:

  • mbr2gpt /validate /disk:0 (Be sure to put the correct disk number here)

I got a layout error when doing this.  turned out it was because there were 4 partitions and mbr2gpt only supports 3.  I deleted the Recovery partition and all was good.

If everything checks out ok you can then run this command:

    • mbr2gpt /convert /disk:0(Be sure to put the correct disk number here)

If success full then reboot and make sure UEFI is the boot type

References:

https://www.windowscentral.com/how-convert-mbr-disk-gpt-move-bios-uefi-windows-10

https://scottiestech.info/2017/11/12/convert-your-windows-10-boot-drive-from-mbr-to-gpt/

https://www.disk-partition.com/windows-10/mbr2gpt-conversion-failed-3889.html