It seems only fair to throw my hat into the ring here too.
I’ll try to include as much information as possible, because through a painful day and a half, I finally have Windows 8.1 running through what I am pretty sure is an EFI setup -- however I haven’t seen any instructions here on how to determine that for sure.
I have a late 2013 Retina MBP with the nVidia card. I wanted to install Windows 8.1 Pro through EFI. I tried many of the steps here, and finally one worked. This was after many failures, so bear with me. I will be borrowing from many of the steps that others before me have used.
I created a USB installer with Bootcamp Assistant on my rMBP. I used a en-US Windows 8/8 Pro ISO from MSDN.
If you’ve tried this and failed multiple times like I did, uncheck the first two options in Boot Camp Assistant and check the third option to “Remove Windows 7”. Return your system back to a single-harddrive partition state.
Close Boot Camp Assistant.
Open up Disk Utility. Go to the top of the heirarchy of your harddrives, and go to the First Aid tab. Verify the Disk and Repair it, until there are no errors remaining. I had to do this a few times.
Re-open Boot Camp Assistant. Plug in your USB Drive containing your Windows 8 Installer, and check only the third option on the Assistant. Partition your drive for Windows to your liking.
Your computer will restart. hold down Option, and boot back into your Mac.
- Open up Disk Utility.
- Click on the Top Level HardDrive in the list.
- Click on the rectangle that says “Bootcamp”.
- Delete it with the “minus” button. (Originally, I couldn’t find this minus button because I was selecting the partition in the left list. Don’t do that.)
- Create a new partition by clicking the plus button. Select the ExFAT option. Name it “BOOTCAMP” again to make our lives easy.
- Click Apply
Restart your computer. Hold down Option. Boot into the USB “Windows” Icon. (We will install the BIOS version of Windows, and then remove the MBR and repair EFI.)
During the Windows 8 installation, you will need to select the “BOOTCAMP” partition and format it. You should be able to continue at this point.
The installation should succeed. When the computer restarts, hold down Option and select the Harddrive icon for “Windows”. Do this until you reach the “Personalize” section of the installation. Turn off your computer by pressing the power button on your laptop.
Turn the computer on, and hold down Option. Boot into your Mac side.
Download and install gdisk ( http://sourceforge.net/projects/gptfdisk/ )
The PKG will not run out of the box, you need to give permission in System Preferences > Security & Privacy > General Tab
After gdisk is installed, open up a Terminal prompt.
type:
sudo gdisk /dev/disk0 (hit enter)
x (hit enter)
n (hit enter)
w (hit enter)
y (hit enter)
(if the app hasn’t quit out for you at this point)
q (hit enter)
Close the terminal.
Open your USB Drive, and rename AutoUnattended.xml to AutoUnattended.xml.back
Reboot the computer, Hold Option down, now select the USB EFI Boot so we can fix EFI. (You’ll notice your Windows drive is missing for now.)
When the installer starts, hit Shift-F10.
type:
diskpart (hit enter)
list volume (hit enter)
select volume 1 (hit enter -- make sure volume 1 is the 200mb EFI volume)
assign letter=B (hit enter)
exit (enter)
cd /d B:\EFI\Microsoft\Boot\ (hit enter)
ren BCD BCD.bak (hit enter)
bcdboot C:\Windows /l en-US /s B: /f ALL (hit enter)
When this is done, you should be good. Reboot, hold Option down one more time, and go back into the Hard Drive that says “Windows”.
Finish your initialization of Windows 8.1.
Don’t forget to install the BootCamp drivers
Thanks to everyone that suggested stuff on here. I hope something gets straightened out, this was far too painful to deal with. 🙂
