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Level 1

15 points

The ultimate way to install Windows 8.x in (U)EFI mode on Apple systems

Well, all these solutions regarding Windows 8 (or 8.1) installation methods in this forum seem to be quite complicated. Here follows my favourite way for installing Windows 8.x on Apple EFI systems.

First, once and for all, forget Boot Camp! Because Windows 8 is fully EFI compliant, Boot Camp is totally useless. You only need it to get all the Windows drivers. When using Boot Camp with Windows 8 in EFI mode you get very likely even greater problems. The root of the most Windows 8 install errors reported here is located in Apple’s special "hybrid MBR" GPT layout. Nothing else!

So, in consequence, you have just to remove / replace that "hybrid MBR" with a standard GPT "protective MBR". This change will NOT affect OS X or any other OS X program in any way!

1. Use the OS X Disk Utility to create a partition scheme of your wishes.

2. Download in OS X the tool "GPT fdisk". Install it and start it in terminal with:

sudo gdisk /dev/disk0 or sudo gdisk /dev/disk1

Type p to view the partition table (verify that you have selected the right drive)

Type x to enter experts menu

Type n to create a new clean "protective MBR" (GPT fdisk will NOT report any changes)

Type w to save your changes

3. Start Windows 8 setup in EFI mode; - switch to "Windows prompt" under "repair tools". Start command diskpart. Check your partition; - select that one with name "EFI". Add the drive letter "b" with the command assign letter=b. (Note, this point is perhaps not needed at some systems.)

4. Exit diskpart, start again Windows 8 setup installer from prompt with command setup.

In Windows setup you have now just to format the Windows partition, - the setup installer is now able to update the Apple EFI Boot record properly. You should not get the "Windows could not update the computer's boot configuration. Installation cannot proceed." message.

I can confirm that this install method has worked perfectly for several MacBook, iMac and Macmini computers. Furthermore you should be also able to install Linux smoothly with EFI mode in dual or triple boot configurations. (Don’t know but Linux may have the same troubles like Windows with Apple’s "hybrid MBR" GPT layout.)

Finally big thanks to Roderick W. Smith for his great GPT fdisk tool!! And also a big thanks to user "riseyth" which has given the diskpart EFI "assign letter =b" hint in this forum. (list of references: http://superuser.com/questions/508026/windows-detects-gpt-disk-as-mbr-in-efi-boo t/508454#508454)

Posted on Apr 16, 2014 11:54 AM

58 replies

Loner T

Level 9

59,471 points

Sep 1, 2015 4:43 AM in response to Ole_Oie

Ole_Oie wrote:

I have few few questions.

I have OS 10.10 and windows 10 already installed with bootcamp. Do I need to partition the disk again in step 1?

In step 2 on which disk I do the sudo command. Below is the structure of the SSD?

Thank you.

If you already have Windows installed, and it is functional, is there a need to do this at all?

Ole_Oie

Level 1

10 points

Sep 1, 2015 6:43 AM in response to Loner T

It fully functional just the SSD is running in IDE in windows. I would like it to use the AHCI.

It is early 2011 macbook pro. I tried the BOOTICE it installs the AHCI and the SSD goes from 340Mb/s to 560Mb/s, but affects the sleep/wake mode of the windows.