EFI install of Windows 10 on external USB3 drive.

Gjwilly

macrumors 68030
Original poster
May 1, 2011
2,872
509
SF Bay Area
Hello all,

Just a quick guide for some people who may want to install Windows in an external drive (USB/TB) in a UEFI environment.

Note: The drive enclosure should support UASP.

Connect external drive to a Windows VM. You must have a Windows VM in VMware/Parallels.

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

Open elevated cmd.exe

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
Type create partition EFI size=100
Type format quick fs=fat32 label=EFI
Type assign letter=S
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

Restart your entire Mac. After the chime, hold down Option and when prompted to select your boot drive, select EFI Boot.

Proceed installation normally.

After installation, install Boot Camp drivers.

Hope it helps.

Note: If you have an install.esd file instead of install.wim, follow the guide here to convert it into a .wim file.

http://www.intowindows.com/how-to-easily-convert-install-esd-to-install-wim/
I tried to follow the guide above using a 2013 MacBook Air and a VMware version of Windows 10 but for some reason, the USB drive (an old SSD from an rMBP in an OWC USB-3 enclosure) would not be recognized by the virtual Windows. I finally ended up using an actual PC running Windows 10 and it recognized the drive without problem.

I also had the problem of having an install.esd file instead of an install.wim file.
I tried the program suggested in the intowindows link but I guess it's no longer freeware.
The comments in that same intowindows article mention a different program, ESD2WIM-WIM2ESD, and that one was free and worked.
Just be sure to check your drive letters when following the above guide because the process of converting the install.esd to install.wim will add and remove some virtual drives on its own.

I finished creating the drive on the Windows PC and then moved it to my 2014 rMBP and it option-booted just fine.

Once I had Windows 8 running off of the USB drive I rebooted to OS X and ran Bootcamp Assistant to get the Bootcamp drivers.
Returned to Windows 8 to install the drivers and then did an in-place upgrade to Windows 10 using the save nothing option. That was the longest part of the whole process -- probably took almost 2-hours.
Windows 10 finally booted and I again installed the Bootcamp drivers.
Whole thing probably took around 3-hours.
 

versacedu

macrumors newbie
Jan 10, 2016
2
0
I tried to follow the guide above using a 2013 MacBook Air and a VMware version of Windows 10 but for some reason, the USB drive (an old SSD from an rMBP in an OWC USB-3 enclosure) would not be recognized by the virtual Windows. I finally ended up using an actual PC running Windows 10 and it recognized the drive without problem.

I also had the problem of having an install.esd file instead of an install.wim file.
I tried the program suggested in the intowindows link but I guess it's no longer freeware.
The comments in that same intowindows article mention a different program, ESD2WIM-WIM2ESD, and that one was free and worked.
Just be sure to check your drive letters when following the above guide because the process of converting the install.esd to install.wim will add and remove some virtual drives on its own.

I finished creating the drive on the Windows PC and then moved it to my 2014 rMBP and it option-booted just fine.

Once I had Windows 8 running off of the USB drive I rebooted to OS X and ran Bootcamp Assistant to get the Bootcamp drivers.
Returned to Windows 8 to install the drivers and then did an in-place upgrade to Windows 10 using the save nothing option. That was the longest part of the whole process -- probably took almost 2-hours.
Windows 10 finally booted and I again installed the Bootcamp drivers.
Whole thing probably took around 3-hours.
Hello,
I am having an iMac, and it is currently running Mac OS X, and I just bought an external ssd, and I would like to install windows 10 on it, and then use it to boot into Windows on my iMac when need to. However, I don't have have any clues how to do that. I have also bought an enclosure for the ssd.

I also purchased a copy of genuine windows 10 Home version from Microsoft (usb version)

Can someone please send me steps how to do that? Thanks so much in advance.
 

Fancuku

macrumors 65816
Oct 8, 2015
1,009
2,540
PA, USA
Unless things have changed with W10, Windows never allowed you to install on an external USB drive. You needed to use an external thunderbolt drive because Windows sees Thunderbolt as a PCI-E device which allows for installation.
 

Gjwilly

macrumors 68030
Original poster
May 1, 2011
2,872
509
SF Bay Area
Can someone please send me steps how to do that? Thanks so much in advance.
The steps are in the first post. The guide I quoted has all of the info that I needed to install Windows 8 on my external USB drive. I then upgraded to Windows 10.
You need a 64-bit version of Windows 8 or higher with a valid activation key, a USB-3 enclosure that will be recognized in both the OS X and the virtual Windows environment (that was my problem -- my drive wasn't recognized in my virtual Windows machine -- I had to use an actual Windows machine), and you need a Mac that fully supports UEFI booting.
[doublepost=1452710071][/doublepost]
Unless things have changed with W10, Windows never allowed you to install on an external USB drive. You needed to use an external thunderbolt drive because Windows sees Thunderbolt as a PCI-E device which allows for installation.
The guide I followed worked with USB-3 and Windows 8.
 

user97908

macrumors newbie
May 1, 2016
25
0
Washington
someone have the info to do it from a mac ? i don't have any windows oriented computer, only el capitan and debian linux. i would like to do the same things but from mac (or linux). someone should put some efi folder on deposit it would be helpfull. this guy on ebay sell his applied method.
 

ActionableMango

macrumors G3
Sep 21, 2010
9,263
6,249
this guy on ebay sell his applied method.
Hahaha, the seller's notes make no sense:

"This listing is sold with a FAULTY RAM with eBay's Listing guidelines." Soooo... this is faulty RAM?

"Items contained on the product are under the terms of the GNU License, the GNU Lesser General Public Licenses (LPGL) or the Mozilla Public License."
Really? Microsoft uses Mozilla Public License for Windows?

"Fully complies with Microsoft policy for Creating a backup system image of Windows."
I doubt Microsoft's backup policy permits you to sell your Windows system backups for profit.
 

Gjwilly

macrumors 68030
Original poster
May 1, 2011
2,872
509
SF Bay Area
Hahaha, the seller's notes make no sense:

"This listing is sold with a FAULTY RAM with eBay's Listing guidelines." Soooo... this is faulty RAM?
He's reselling Microsoft licenses and the terms for OEM licenses require that they only be sold along with actual hardware. The faulty ram is the hardware. Its faulty but he's doing that so that he can claim that hes honoring Microsoft's and ebay's terms
 

Fancuku

macrumors 65816
Oct 8, 2015
1,009
2,540
PA, USA
I've bought Dell OEM Windows 7 installation disks on ebay before and the seller included a stick of old ddr2 ram. They have to comply with the ebay rules and that's how they get around it. Nothing wrong with it in my opinion.
 

Gjwilly

macrumors 68030
Original poster
May 1, 2011
2,872
509
SF Bay Area
Its a rule that keeps the honest honest but does nothing to curb the dishonest.
A genuine reseller is one thing. A guy who just scavenges license stickers from discarded computers is another.