My setup: Mac Pro 6,1 QC/32/256/D300, and an external Thunderbolt HD with a GUID partition table and a 500GB WINDOWS partition. This partition was initially made and formatted in Disk Utility with an MS-DOS filesystem.
Preparations
Replace Bluetooth mouse and keyboard with USB versions. My Windows 8.1 source was the 64-bit DVD, which will not install from the Apple USB SuperDrive (that dreaded "A media driver your computer needs is missing..." message). I used another make USB BD/DVD/CD reader, common in the PC world, instead.
The Apple driver software will be installed when the Windows installer has finished. It is handy to let Boot Camp Assistant prepare the appropriate USB memory stick. If you're not using a DVD, then Boot Camp Assistant can also make a bootable USB memory stick with the Windows 8.1 installer.
But note: don't let Boot Camp Assistant do any repartitioning of the internal SSD. We'll install directly to the external HD.
Format WINDOWS partition
Reboot while holding the Alt-key, then select the Windows installer for booting, in my case (EFI) DVD/CD. Watch out: there is a brief opportunity to confirm this boot method by pressing a key, otherwise good old OS X will reboot. Select the option to "repair your PC", obtain a CLI terminal and type the command diskpart to enter this utility. The diskpart command
will show the number x of the external HD (in my case 2). Select this disk and show its partitions with
showing the WINDOWS partition as number y (it was 4 in my case). Select and format this partition with
and the result can be checked with
with self-explanatory output. We're done, so repeatedly exit and shut down the Mac.
Reset PRAM
A reset of non-volatile RAM (PRAM) is recommended at this point, also if you leave the actual installation of Windows 8.1 for later. So, give the four-finger salute Alt-Cmd-P-R until the chime has sounded at least two times.
Install Windows 8.1
Reboot the 64-bit Windows 8.1 installer, as before, but this time choose to install. Select a Custom installation, and be sure to point to our prepared WINDOWS partition as the installation target. There is no need to format this partition, since we've already done that.
There will be a few reboots, hold the Alt-key each time but now select the new Windows to boot (not the installer).
Install BootCamp software
With Windows 8.1 installed and running, insert the prepared USB stick, and (using File Explorer) click on setup.exe in the bootcamp folder on the stick, which installs drivers and other software. This will take a while.
Another reboot, this time without holding the Alt-key, and the Bluetooth keyboard and mouse will work, as will the Airport card and other typical Apple hardware.
I prefer OS X to be the default, so click on the BootCamp icon (under Hidden Icons) in the lower right corner to configure this.
Working with Windows
I use Winclone, running from OS X, to make a backup of this Windows 8.1 installation to another HD, in my case a USB-3.0 HD. This backup is not itself bootable, but can be placed back on the original WINDOWS partition and then it will be.
Enjoy!
Preparations
Replace Bluetooth mouse and keyboard with USB versions. My Windows 8.1 source was the 64-bit DVD, which will not install from the Apple USB SuperDrive (that dreaded "A media driver your computer needs is missing..." message). I used another make USB BD/DVD/CD reader, common in the PC world, instead.
The Apple driver software will be installed when the Windows installer has finished. It is handy to let Boot Camp Assistant prepare the appropriate USB memory stick. If you're not using a DVD, then Boot Camp Assistant can also make a bootable USB memory stick with the Windows 8.1 installer.
But note: don't let Boot Camp Assistant do any repartitioning of the internal SSD. We'll install directly to the external HD.
Format WINDOWS partition
Reboot while holding the Alt-key, then select the Windows installer for booting, in my case (EFI) DVD/CD. Watch out: there is a brief opportunity to confirm this boot method by pressing a key, otherwise good old OS X will reboot. Select the option to "repair your PC", obtain a CLI terminal and type the command diskpart to enter this utility. The diskpart command
Code:
list disk
Code:
select disk x
list partition
Code:
select partition y
format fs=ntfs label="WINDOWS" quick
Code:
list volumeReset PRAM
A reset of non-volatile RAM (PRAM) is recommended at this point, also if you leave the actual installation of Windows 8.1 for later. So, give the four-finger salute Alt-Cmd-P-R until the chime has sounded at least two times.
Install Windows 8.1
Reboot the 64-bit Windows 8.1 installer, as before, but this time choose to install. Select a Custom installation, and be sure to point to our prepared WINDOWS partition as the installation target. There is no need to format this partition, since we've already done that.
There will be a few reboots, hold the Alt-key each time but now select the new Windows to boot (not the installer).
Install BootCamp software
With Windows 8.1 installed and running, insert the prepared USB stick, and (using File Explorer) click on setup.exe in the bootcamp folder on the stick, which installs drivers and other software. This will take a while.
Another reboot, this time without holding the Alt-key, and the Bluetooth keyboard and mouse will work, as will the Airport card and other typical Apple hardware.
I prefer OS X to be the default, so click on the BootCamp icon (under Hidden Icons) in the lower right corner to configure this.
Working with Windows
I use Winclone, running from OS X, to make a backup of this Windows 8.1 installation to another HD, in my case a USB-3.0 HD. This backup is not itself bootable, but can be placed back on the original WINDOWS partition and then it will be.
Enjoy!