Here’s the case: I’m installing Windows 10, but even when formatting a hard drive in the installer Windows still won’t install, but complains about MBR, EFI, GPT, whatever. The issue lies within the MBR that is on the target disk, and it needs to be converted to GPT:
shift + F10to open the command prompt in the Win 10 installer
diskpartto start the Disk Partitioner application
list diskto show all disks
select disk #where # is the target disk, as indexed by
cleanWarning: This empties the target disk!
convert gptto finally convert MBR to GPT.
After this the target disk should be empty and ready for Win 10 installation.