Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Not yet tried myself, and unsure if this info is common knowledge, but certainly keen on getting this up and running once I've got a spare box to try it on:

http://www.reddit.com/r/mac/comments/2fy3be/by_popular_demand_my_better_than_bootcamp_guide/

Boot Camp Assistant on Haswell and later Macs already install Windows 8.1 in UEFI by default.

I also made a way to get Windows on an external drive running on a Mac.

Connect external drive to Windows VM. You must have a Windows VM in VMware/Parallels/VBox, or a Windows PC. Any existing Windows environment will do.

Note: If you’re using a 32-bit ISO, your Windows environment used to do these commands have to be 32-bit. And if it’s a 64-bit ISO, the environment has to be 64-bit.

What you need:
install.wim file (obtain this from your Windows ISO)

Open elevated cmd.exe (run as admin)

Note: All commands aren't case sensitive, including pathway to files.

Type diskpart
Type list disk
Take note of the disk you want to select
Type select disk 1 (if your disk is Disk 1)
Type clean
Type convert gpt (do this and then stop at this point if you're using a drive with a Thunderbolt port. If installing in BIOS-CSM, type convert mbr and then stop at this point if you’re using a drive with a Thunderbolt port)
Type create partition EFI size=100 (skip if installing in BIOS-CSM)
Type format quick fs=fat32 label=EFI (skip if installing in BIOS-CSM)
Type assign letter=S (skip if installing in BIOS-CSM)
Type create partition primary
Type format fs=ntfs quick label=W2G (or any other name you wish for label)
Type assign letter=E
Type exit

Open up File Explorer. In your C drive, create a new folder named WIN2GO.
Put the install.wim file in this folder

Back in cmd.exe:
Type dism /apply-image /imagefile:C:\WIN2GO\install.wim /index:1 /applydir:E:\ (this process will take quite a while)
Type E:\Windows\System32\bcdboot E:\Windows /s S: /f UEFI (use this one for UEFI installation)
Type E:\Windows\System32\bcdboot E:\Windows /s E: /f ALL (use this one for BIOS-CSM installation)

Restart your entire Mac. After the chime, hold down Option and when prompted to select your boot drive, select EFI Boot (or whatever else that comes up for a BIOS-CSM installation).

Proceed installation normally.

After installation, install Boot Camp drivers. Feel free to trash the VM once you're done too.

For best results, use USB 3/Thunderbolt. If you don't have USB 3, use Thunderbolt. If you have neither, stick back to the internal drive :)

Don’t use a USB stick.

Note: This method involves reformatting the entire external drive.

For Thunderbolt drives, just boot from the Windows USB installer and install directly onto the TB drive. Windows sees TB drives as an internal PCIe connection. However, you must format the TB drive as GPT first.

CAUTION: Windows can only be installed in UEFI flawlessly on Haswell Macs and later. Ivy Bridge and earlier Macs can only run Windows in BIOS-CSM flawlessly. Attempts to boot a UEFI installation of Windows on an Ivy Bridge or earlier Mac will result in driver issues.

These steps do not work with Windows 7, as it lacks the dism.exe utility.

UEFI-compatible Macs:
MacBook Air (mid-2013 and later)
iMac (late-2013 and later)
Retina MacBook Pro (late-2013 and later)
Mac Pro (trashcan shape)
Mac Mini (late-2014 and later)

Non-retina MBPs, along with other Macs not listed above (basically all Ivy Bridge and older Macs), are not UEFI compatible.

WinToUSB basically does the same thing, but doesn’t always work because WinToUSB doesn’t really take into account between BIOS-CSM and UEFI Macs; it only uses one method for all (which may result in boot failures and other problems).
 
Last edited:
I am trying to install Windows 8.1 Pro x64 on an early 2008 iMac 8,1 with newly installed 500GB SSD Drive. I was running Mavericks (booting up as x64) and decided to follow this 'better than bootcamp' guide.

I created a 8GB USB installation drive for Win 8.1 Pro x64 using Microsoft's Media Creation Tool. The creation process verified that it was correctly created so I'm sure it's not corrupted.

I can't seem to boot up the computer from this Windows 8.1 Pro USB drive however. In the OS X boot manager (booting up and holding down Alt), if I click on the Windows 8.1 USB drive (EFI Boot) icon, the computer immediately freezes, the mouse pointer won't move and I have to shut down my computer.

I tried running rEFIt (having wiped the computer and installed the original OS on it, Leopard, to experiment with a few things with bootcamp), and that didn't work either, although it did seem to help slightly.

In the rEFIt menu, I have:
- OS X partition (OS X symbol)
- Windows XP bootcamp partition that I made (Windows symbol)
- Boot bootmgr.efi from ESD-USB (Windows symbol)
- Boot EFI/boot/bootx64.efi from ESD-USB (Qbert symbol)

The Boot bootmgr.efi option comes up with an error - the screen goes black and it starts but then fails immediately. The computer doesn't crash.

The EFI/boot/bootx64.efi fairs much better, I get the black screen and loading bar for loading files and it continues to load for about 5 minutes until the screen goes completely blank and the computer seems to have crashed and is unresponsive, so I have to shut the computer down and reboot it and go into the boot menu again. Has this happened to anyone?

Is there something I can do to try to get this x64 Win 8.1 USB to run? Without solving this problem, I can't get beyond the first step in the 'better than bootcamp' guide.

I figured a fallback plan would be to at least get Win 8.1 x64 working in bootcamp, as I've read others have managed it - so as I said above I wiped the machine, reinstalled Leopard, created an XP partition, installed the XP ok using NTFS instead of FAT32, then figured I could run the Win 8.1 installation USB from there and overwrite XP - however, as it's Win XP x86, it can't run the Win 8.1 x64 installer file, so I'm guessing the best I could achieve using this method would be to create an install USB for Win 8.1 x86 and install this instead, which isn't really what I want to achieve.

Any feedback would be greatly appreciated! Cheers.
 
Last edited:
I am trying to install Windows 8.1 Pro x64 on an early 2008 iMac 8,1 with newly installed 500GB SSD Drive. I was running Mavericks (booting up as x64) and decided to follow this 'better than bootcamp' guide.

I created a 8GB USB installation drive for Win 8.1 Pro x64 using Microsoft's Media Creation Tool. The creation process verified that it was correctly created so I'm sure it's not corrupted.

I can't seem to boot up the computer from this Windows 8.1 Pro USB drive however. In the OS X boot manager (booting up and holding down Alt), if I click on the Windows 8.1 USB drive (EFI Boot) icon, the computer immediately freezes, the mouse pointer won't move and I have to shut down my computer.

I tried running rEFIt (having wiped the computer and installed the original OS on it, Leopard, to experiment with a few things with bootcamp), and that didn't work either, although it did seem to help slightly.

In the rEFIt menu, I have:
- OS X partition (OS X symbol)
- Windows XP bootcamp partition that I made (Windows symbol)
- Boot bootmgr.efi from ESD-USB (Windows symbol)
- Boot EFI/boot/bootx64.efi from ESD-USB (Qbert symbol)

The Boot bootmgr.efi option comes up with an error - the screen goes black and it starts but then fails immediately. The computer doesn't crash.

The EFI/boot/bootx64.efi fairs much better, I get the black screen and loading bar for loading files and it continues to load for about 5 minutes until the screen goes completely blank and the computer seems to have crashed and is unresponsive, so I have to shut the computer down and reboot it and go into the boot menu again. Has this happened to anyone?

Is there something I can do to try to get this x64 Win 8.1 USB to run? Without solving this problem, I can't get beyond the first step in the 'better than bootcamp' guide.

I figured a fallback plan would be to at least get Win 8.1 x64 working in bootcamp, as I've read others have managed it - so as I said above I wiped the machine, reinstalled Leopard, created an XP partition, installed the XP ok using NTFS instead of FAT32, then figured I could run the Win 8.1 installation USB from there and overwrite XP - however, as it's Win XP x86, it can't run the Win 8.1 x64 installer file, so I'm guessing the best I could achieve using this method would be to create an install USB for Win 8.1 x86 and install this instead, which isn't really what I want to achieve.

Any feedback would be greatly appreciated! Cheers.
You have to use the BIOS-CSM method. Your Mac doesn't support UEFI.

I have updated my post for the updated steps.
 
Thanks for the response. I didn't initially read through your write up as it seems to be describing the procedure for an external drive rather than an internal one.

I have WinXP x86 on a partition and also in a VM. The Win 8.1 x64 installer USB won't work in either of these places to run its cmd.exe. I could run the XP cmd.exe, either in a VM or on the XP bootcamp partition, would that work? I would assume that the commands would work the same in XP or Win 8.1 but I'd have to be booting off an external drive if I was reformatting the entire hard disk. There is no 'install.wim' file on the Win 8.1 Pro installer USB.

I meant to mention in my previous post that there was another option in rEFIt to boot up Windows from the ESD-USB and clicking on that made the screen go black and displayed a grey windows symbol, which looked like a Win 8.1 Pro installer but after a few seconds of this, the screen changed to booting up Win XP from the partition on my hard drive, which was presumably the designated start up disk at the time.

Cheers.

BTW I'm assuming the OP has tried it yet?
 
Thanks for the response. I didn't initially read through your write up as it seems to be describing the procedure for an external drive rather than an internal one.

I have WinXP x86 on a partition and also in a VM. The Win 8.1 x64 installer USB won't work in either of these places to run its cmd.exe. I could run the XP cmd.exe, either in a VM or on the XP bootcamp partition, would that work? I would assume that the commands would work the same in XP or Win 8.1 but I'd have to be booting off an external drive if I was reformatting the entire hard disk. There is no 'install.wim' file on the Win 8.1 Pro installer USB.

I meant to mention in my previous post that there was another option in rEFIt to boot up Windows from the ESD-USB and clicking on that made the screen go black and displayed a grey windows symbol, which looked like a Win 8.1 Pro installer but after a few seconds of this, the screen changed to booting up Win XP from the partition on my hard drive, which was presumably the designated start up disk at the time.

Cheers.

BTW I'm assuming the OP has tried it yet?

You can only use Windows 8. Not even Windows 7 will do, as it does not have dism.exe in it.

If you have an install.esd file instead of install.wim, my steps are useless.

In your case, why not just use a Windows 8 ISO file and then use Boot Camp Assistant? It'd be easier and more straightforward.
 
You can only use Windows 8. Not even Windows 7 will do, as it does not have dism.exe in it.

If you have an install.esd file instead of install.wim, my steps are useless.

In your case, why not just use a Windows 8 ISO file and then use Boot Camp Assistant? It'd be easier and more straightforward.

Thanks for the input.

My Win8.1Pro installation USB contains the .esd file and not the .wim file:

ESD-USB/support/install.esd

The problem here is probably that I used Microsoft's installation media creation tool. After selecting either 32 or 64 bit target system, it has two options, to either create a USB install drive or to save an iso in order to burn a DVD. I presumed that as the original 'BTB' guide specified that it had to be booted from a USB that I should choose the USB option in the media creation tool as it would be easier than saving an iso/creating a DVD and trying to make a USB installer out of that. However, the 'BTB' guide specified creating a USB install drive from an .iso, so I could go back and try doing that. Do you think that would allow the USB to then boot up on my machine?

http://windows.microsoft.com/en-GB/windows-8/create-reset-refresh-media

My early 2008 24" 8,1 iMac's bootcamp does not support Win 8, it only supports x86 versions of Win 7, Vista and XP, otherwise I would have done this at the outset.

https://support.apple.com/en-gb/HT204048

If I managed to get the install USB to work with a virtual machine on an external drive, would I be right in assuming that I might be able to perform the reformatting and installation operation of my internal drive from there?
 
Last edited:
Thanks for the input.

My Win8.1Pro installation USB contains the .esd file and not the .wim file:

ESD-USB/support/install.esd

The problem here is probably that I used Microsoft's installation media creation tool. After selecting either 32 or 64 bit target system, it has two options, to either create a USB install drive or to save an iso in order to burn a DVD. I presumed that as the original 'BTB' guide specified that it had to be booted from a USB that I should choose the USB option in the media creation tool as it would be easier than saving an iso/creating a DVD and trying to make a USB installer out of that. However, the 'BTB' guide specified creating a USB install drive from an .iso, so I could go back and try doing that. Do you think that would allow the USB to then boot up on my machine?

http://windows.microsoft.com/en-GB/windows-8/create-reset-refresh-media

My early 2008 24" 8,1 iMac's bootcamp does not support Win 8, it only supports x86 versions of Win 7, Vista and XP, otherwise I would have done this at the outset.

https://support.apple.com/en-gb/HT204048

If I managed to get the install USB to work with a virtual machine on an external drive, would I be right in assuming that I might be able to perform the reformatting and installation operation of my internal drive from there?

Making a USB installer would be a far more viable option.

In my opinion, it's easier to use ISO to USB (free app for Windows) on your existing Windows system and use it to make a bootable USB out of the ISO that you have. I personally use ISO to USB myself to create bootable Windows USB sticks.
 
Making a USB installer would be a far more viable option.

In my opinion, it's easier to use ISO to USB (free app for Windows) on your existing Windows system and use it to make a bootable USB out of the ISO that you have. I personally use ISO to USB myself to create bootable Windows USB sticks.

Thanks for the input. What I'm saying is that MS's media creation tool has the option to create an install USB directly, without using an ISO, which is the option I chose. I guess without you having used this media creation tool, you can't comment, but if it doesn't have the .wim then evidently it isn't going to work for this application, so I guess downloading the ISO is the next option. Cheers.
 
I tested the concept just now by downloading MSDN Windows 8.1 Enterprise x64 iso. I didn't have a Win 7 machine to hand to be able to download the actual Win 8.1 Pro iso.

I made a bootable USB out of the Win 8.1 Enterprise ISO using ISO to USB on WinXP, checked to see that it had the install.wim file in there, which it did, then restarted to see if Win 8.1 Ent. booted up in rEFIt or not. I had exactly the same results as trying to boot up from the Win 8.1 Pro x64 USB which I made with the media creation tool (which did not contain the install.wim file). Am I correct in thinking that this is the correct procedure please? Thanks in advance for any pointers!

I did try creating a Win 8 VM using this x64 Enterprise ISO in VirtualBox and it does seem to work that way at least.

I read somewhere that those who were trying to install Win 7 or 8 x64 on an early 2008 iMac had to modify the installation disk in some manner to get it to install although I didn't find any specifics.
 
Last edited:
You have to use the BIOS-CSM method. Your Mac doesn't support UEFI.

I have updated my post for the updated steps.
Yjchua95,

I tried to answer on reddit, but cannot.

I could install Windows, so am at the step of the Mac OS X re-installation.

I could not use Bootcamp, because I have an OWC SSD in PCIe in a Mac Pro 5.1, which is detected as being in a RAID matrice, (the RAID notation figured only on the other slot), and this is not allowed by Bootcamp - surely for safety purpose.

But I have an unmodifiable partition (disk0s2) before Windows (not after), and when I try to add your partitions, the preparation to partitions last for ages. Is it due to a limitation to 3 partitions ? (I should obtain four).

I hope you or someone else will agree to help me. Thank you very much in advance.
 
Finally, I followed this tutorial:
http://technology.siprep.org/install-windows-dual-boot-to-mac-pro-using-owc-ssd/
and it worked fine.
Although I wished to, I did not try the "legacy" installation option, to avoid additional barriers.

Oh, the first re-boot options are almost humorist: You'll get as a copyright info at the top, and some of the icons (except the one corresponding to the Mac partition) are barely well designed, what may cause worries to some.

But the license info is deleted after Windows installation, and the icons re-become standard. It is a proper installation for me - these guys of source-forge did an excellent work.

I could re-boot on Mac after Windows installation, and saw that the needed rEFInd automatically thrown itself to the waste bin.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.