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I want to install Windows 7 on an external hard drive, and boot from it when needed.

Is this possible on a Mac? I have heard from some sources that it is not possible to boot Windows from external drives, at least on the new Macs. I found this quite surprising.

Any idea if this is true?

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possible duplicate of Boot Macbook pro from external harddisk –  jtbandes Apr 18 '12 at 15:32
    
apparently rEFIt doesnt work ... –  Newton Apr 19 '12 at 9:40
    
Doesn't work for what? I've used it to triple-boot before... –  jtbandes Apr 19 '12 at 11:25
    
from an external? what Mac were you using and what OS did it have installed? –  Newton Apr 19 '12 at 12:38
    
Ah no, just internal, sorry... –  jtbandes Apr 19 '12 at 12:43

7 Answers 7

It is possible, but it's not straight forward. This detailed step by step guide (which I did) contains all you need to know to install and run Windows 7 or 8 from an external drive (USB3 or thunderbolt): http://bleeptobleep.blogspot.fr/2013/02/mac-install-windows-7-or-8-on-external.html

To sum up, this guide will help you:

  • Get the Windows installation pack from a DVD or ISO file
  • Partition and format your external drive to make it bootable
  • Deploy Windows on your external drive
  • Boot on your external drive
  • Install Windows
  • Download and install the bootcamp drivers (without even using the bootcamp assistant)
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Could you please summarize the information here and not just give a link. See these meta questions and here –  Mark Feb 4 '13 at 13:51
    
Sorry, I added a summary now. Is it sufficient? –  BleepToBleep Feb 4 '13 at 14:26
    
Hey, please anybody could confirm if it is working ? P.S.: my setup : MBA 2013 + 2 TB WD USB3 External(having 4 partitions 1st NTFS and rest 3 exFAT) –  jeet.chanchawat May 10 at 21:02

Bootcamp simply isn't designed to install Windows on an external drive.

7. If I have more than one hard drive, can I install Microsoft Windows on any drive?

You can use Boot Camp to install Windows on any internal hard drive, but not on an external hard drive.

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There is always the possibility to run Windows 7 as a virtual image (e.g. VMWare, VirtualBox). Works well from an external drive and has the advantage that you can start the image from any computer that has the software installed.

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Silly as I am I wanted to do the same a few weeks ago. But the Windows 7 installer told me that it can't be installed on an external (USB or Firewire) drive.

You could probably installed a Windows PE version. But since that's not the Real Deal it wasn't an option for me.

Update There's a How-To Install Windows 7 on an external drive which I gonna try in the next few days. Not sure if that's gonna work on a Mac.

Update 2 I tried to install Windows 7 on an external USB drive following the How-To in the first Update. Unfortuantely I didn't get it to work. Getting it copied to the external drive worked well but after rebooting I got an error about not finding this Windows installation.

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for straightforward-method, you can install and run a bootcamp Windows on thunderbolt drive

Bootcamp Windows does not support for usb and firewire external drive, but do support for thunderbolt drive

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

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Could you elaborate on how Bootcamp runs on an external drive. The official instructions explain this is not only not supported, but not achievable without modifying the code or the install steps. –  bmike Feb 26 at 14:44

How-To Install Windows 7 on an external drive . I follow this link and install windows on external. But it doesn't boot on mac. I think mac has a issue of booting windows from usb. It could be about partitioning tables. http://refit.sourceforge.net/ . And i use this rEFIt program. On startup it allows you to choose different os. But this program couldnt help neither.

If anyone knows more please share.

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

I have created a detailed guide here: http://kevtg-compuproductive.tumblr.com

It will work for any Mac, but especially with retina and air users who are having trouble getting other methods to work

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

    
Welcome to Ask Different! While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. –  grgarside Feb 13 at 16:35
    
Kevin can you help me with your tutorial. I dont know what the Silver partition is for i have a 1tb external hdd i want to have windows on and a usb key with windows. So i can't find out what the silver partition is for?. –  user71511 Feb 26 at 14:22

protected by bmike Feb 26 at 14:45

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