You can run the tool from an administrator Command Prompt, but you must add a specific tag to bypass the OS restriction.
The tool is typically run from the but can be used within the full operating system using the /allowFullOS switch. mbr2gpt
This tool is particularly essential for users wanting to upgrade to , as the newer OS requires UEFI and Secure Boot—features that only work on GPT-formatted disks. Why Convert MBR to GPT? You can run the tool from an administrator