I might be late to the game, but just updated a Windows 10 install from MBR to GPT using the “mbr2gpt” command.
However, as many have discovered, the convert results in an error message as shown in this video.
But, as the video shows, once you reboot the system after changing the bios to UEFI, the error goes away and all is well. Why Microsoft hasn’t fixed this is anyone’s guess. Like so many issues with Windows.
