EFI Boot Frozen When Trying to Install Windows 8.1 I am trying to install Windows 8.1 in Bootcamp on my Mac Pro Early 2009 Edition which should be possible according to this page:

https://support.apple.com/en-ap/HT201457

I went through all of the steps and got the software onto my USB drive, etc.  When I reboot the mac and hold the option key I see 3 options.  Main, Restore and EFI Boot, however, when I click the EFI boot, the mouse freezes and nothing happens.

Any ideas on what I should do?

Thanks!

Craig
If you want to EFI boot the installer you need to flash your firmware from MacPro4,1 to MacPro5,1.

Create an installer like mentioned here without any bootmgr files to force an EFI boot.

Remove all disks from Mac Pro to avoid further trouble with Mac EFI looking for MBR or protected MBR.

EFI boot your installer.

Be sure to clean the unneeded Bootcamp partition and create GPT install target.

See also here.