I have had nothing but problems today trying to install Windows 10. Boot Camp Assistant has already created the flash drive for installation and the partition on my hard drive. I restarted and booted into the Windows installer.
The partition created by the BCA gives an error in the Installer saying the selected disk has an MBR partition table, and that on EFI systems, Windows needs to be installed on a GPT disk.
Well, searching on the internet I came across this forum: https://superuser.com/questions/508026/windows-detects-gpt-disk-as-mbr-in-efi-boot .
I completed the steps using gdisk in Terminal. Now, when I boot into the Windows Installer, it just sits there, not loading. And eventually, the flash drive goes inactive.
What am I doing wrong? How do I get past the partition error?
Best Answer
If you changed the file within Boot Camp that allowed you to install from a USB on an older version of the Mac don't bother, it won't work.
If this problem persists just burn the ISO to a blank disc. I used a DVD-R. Then install it from the disc. I recommend restoring the partition to a single partition and uninstall windows with the BCA and try again this time with a disc that has enough space for the ISO.
The gdisk solution in some cases will help for other individuals but for your case I believe you have an old Mac.