Do you have a 3rd party bootloader installed? OR non-apple hardware? You get that error if you are not using the official apple firmware/UEFI bootloader - I sa

Do you have a 3rd party bootloader installed? OR non-apple hardware? You get that error if you are not using the official apple firmware/UEFI bootloader - I saw it a few releases ago when trying to do an install on a machine with an opensource bootloader You will also get it on hackintoshes (OSX on x86 PCs)