Convert Windows 10 installation to boot from UEFI partition.
OR
Repair PC
Command Prompt
or press SHIFT+F10
to spawn command prompt.With command prompt:
diskpart list disk select disk # Note: Select the disk where you want to add the EFI System partition. list partition select partition # Note: Select the Windows OS partition (# number) or your data partition. shrink desired=100 create partition efi size=100 format quick fs=fat32 assign letter=s list partition list volume Note: Note the volume letter where the Windows OS is installed. exit bcdboot X:\windows /s S: