To switch back to UEFI, restart your computer and access the BIOS setup by pressing the appropriate key (often F2, F10, or Delete) during boot. Locate the Boot Mode setting and switch from Legacy ...

If your computer doesn’t offer any options to access its BIOS before your OS loads then it is possible that it uses UEFI instead. On a UEFI-based computer, there is often no button press prompt ...