How to run Boot Camp on External Hard Drive?

I used a sandisk ultra fit usb 3.0 key, and just let bootcamp helper do the install local, the used wintousb to transfer to the key, then bootcamp helper again to remove local windows, usb key boots on it's own 🙂 just make sure you use gpt in the wintousb options

Its possible too with virtualbox.

You can start to install windows in virtualbox, at first step to restart, you should shutdown your virtual machine, and restart your mac with option key.

This is the more easy way.

Now i`m searching for another tutorial to use the usb-win in different macs.

Hi,

I have done everything in order, but when I get to step 19 it doesn't work. Command Prompt says

"Error opening file [F:\sources\install.wim].

The system cannot find the file specified."

What should I do?

I installed windows 10 on an external hdd using disk manager and making partition 100mg of boot and the rest into os storage. I downloaded the bootcamp drivers into an external usb flash drive.

Windows 10 ran fine on my imac 2010. But the problem is that i ranned the set up of bootcamp and it said it was not compatible for windows 10.

It said it could only run on 7, but the setup drivers still executed. And suddemly, the screen went dark. I hear noise when usb is plugged in. But no visual of the os running.

It took me 3 hours to run windows and do all this work on an external hdd.

Please anyone help me with this.

It would be very helpful. How can i see whats going on in the screen?

Any suggestions?

Thank u very much!!

Its easy but the problem is that when you try to install the bootcamp drivers the screen went black completely. It was running windows 10. It was running fine. I even open the booter on my mac. But the problem is... whenever you execute the bootcamp setup from a flash usb to ur external hdd running windows 10, it says is not compatible. It has to be windows 7. So it stopped the execution, then it ranned the setup. Then suddenly my screen went completely black. I heard the usb notifications from windows 10 running, but bootcamp is very OUTDATED. So im installing windows 7 on the external hdd, its alot of work it takes time but well hopefully it does the trick. My head hurts alot been doing this for hours. I guess u need a clean install iso of windows 7. Im doing mine or my convertion from a cd i have of windows 7 on 64 bit

I can confirm that Pierre80's method still works, at least for windows 8.1. Also, if you have a DVD or have made a DVD from an iso file that contains an install.wim file, you don't need to use a virtual disk. It works fine with install.wim file from the DVD. However, do not have windows install DVD in the Mac when you are booting with the external drive. It will look like the external disk is booting, but is actually loading from the DVD and will refuse to install windows on the USB drive. The only other comment is that when windows is installed on an internal disk, the mac will default boot to whatever system it was on last. With the external drive, the default is always OSX. So you have to hold the option key down if you want to boot into windows.I can confirm that Pierre80's method still works, at least for windows 8.1. Also, if you have a DVD or have made a DVD from an iso file that contains an install.wim file, you don't need to use a virtual disk. It works fine with install.wim file from the DVD. However, do not have windows install DVD in the Mac when you are booting with the external drive. It will look like the external disk is booting, but is actually loading from the DVD and will refuse to install windows on the USB drive. The only other comment is that when windows is installed on an internal disk, the mac will default boot to whatever system it was on last. With the external drive, the default is always OSX. So you have to hold the option key down if you want to boot into windows.

Generally Speaking, no, it is not possible.

Boot Camp does not support booting from an external drive in any system, especially not in a notebook. You could try to use a different EFI boot loader (like rEFIt, or rEFInd) but then you will run into the next major hurdle. Until very recently, Microsoft did not support booting any version of Windows from a removable media. Yes, you could build your own custom installers and make it work, but it was not supported. Now recently in WIndows 8 or 8.1, Microsoft has added some support for booting from external drives, but it is a difficult task to accomplish from what I understand.

About the best bet I can see for you would be to buy a Thunderbolt external drive like the Buffalo Ministation (available form Tiger Direct for under $200 USD for a 1TB drive with USB3 and Thunderbolt cables). I believe that you can easily install MacOS on one of those drives and boot/run your Mac from there. I don't think it would allow you to boot Windows from there, but you could still install your Windows programs on a partition on that drive and access them when booted from the internal drive.

My suggestion was that you run MacOS from the external drive, and run Windows from the internal drive, so you should not have any problems running Windows games (when you are running Windows).

Depending upon the games you want to play, you might be able to use virtualization and run Windows in a virtual machine while still running MacOS. If you do this, you could then store your virtual machines on the external drive.

As I said initially, it is not possible using Boot Camp. There are other tools which might help you, and I mentioned those in my first reply as well.

I can report two successes running Windows natively from external hard drives. So what you want is technically possible.

Success 1: I was able to configure Windows 7 to work from external thunderbolt drive (SSD) on MacBook Air mid 2011.

Success 2: I was able to configure Windows 8.1 to work from external thunderbolt drive (2 tb hdd) on MacBook Pro Retina.

In both cases no significant space was uses on the actual internal SSD.

Keep in mind though, MacOs Bootcamp Assistant application just does not implement the needed functionality, so you can't do it via it. If you (or somebody else) is interested in details, I can try to recall and write down the details of what I've done.

I can write down hardware that I have used since I remember it very well.

For thunderbolt drive I have used Seagate GoFlex Thunderbolt Adapter with either Ocz Vertex 3 480 GB SSD or WD Green 2 tb 2.5 inch drive. Worked reliably and easy to assemble since adapter provides a standard SATA connector. The only catch is you might want some "duck tape" to lock the non-standard hdd in place. Or you can go for compatible Seagate 1 TB HDD drive.

Warning: I have tried Samsung 840 Pro with Seagate Thunderbolt Adapter, but it was unstable. Probably not enough electric power supplied via thunderbolt. Or may be because 6gbit SATA was too fast for adapter and it was unstable. I haven't bothered to investigate deeper - I've just used Samsung 840 Pro in a completely different machine as an internal drive.

As far as thunderbolt cables are concerned, both short and long ( 1.5 m) ones worked well.

I suspect Seagate Desktop Thunderbolt Adapter or any other thunderbolt drive will work equally well.

For the MacBook Pro Retina and Windows 8.1 the setup procedure was the following:

Step -1: Make sure your Thunderbot drive works, stable and reliable.

Step 0. Make sure you have a complete Time Machine backup of you Mac OS hard drive. Seriously. Very easy to mess things up completely.

Step 1. Get a Windows 8.1 64 bit iso. You might want to try it out first before committing money to it. For that you can download an official 90 day Windows 8.1 Enterprise evaluation from Microsoft. It's somewhat hidden from mainstream experience, but search engines help you there.

It is important to use 64 bit, as 32 bit will not work.

Step 2. Get a USB flash drive. 8 GB USB flash drive worked fine for me.

Step 3. On Window box or from virtualized Windows machine make a bootable setup USB. I have used Rufus for that. Make sure you have selected "GTP partition scheme for UEFI computer" and FAT32.

I've tried MBR partition scheme, but it hasn't worked for me.

Step 4. Once bootable setup USB is created, shutdown everything. Plugin your external thunderbolt drive and bootable setup USB flash drive. Hold ALT (Option key) to choose from what thing to boot.

Step 5. If you are lucky you will see yellow "EFI Boot". Yellow usually meens 'external'. That meens you are going to boot into setup from USB flash drive. Go for it.

Step 6. In 5-10 minutes you should get into Window setup. Whenever you are asked, always choose "Custom" or so, till you get to the hard drive selection screen. You should see list of many partitions coming from 2 drives - one internal and one external.

WARNING: Be super careful here!!!!!

Step 7. Convince Windows to install itself on the drive that is external. You might have to delete all of the partitions of the external drive and leave it completely unpartitioned. This will make Windows autoconvert it's partition scheme to GTP.

WARNING: Think twice before deleting any partitions; do not delete any partitions on your internal drive.

Step 8. Let Windows install itself. I recommend turning off windows autoupdate for now, especially drivers part of it, since Windows 8.1 autoudate seams to be pushing buggy drivers at the moment.

Step 9. If you are SUPER lucky after reboot (and holding ALT/Option) you should see gray "EFI boot" that will boot Windows from external drive.

Step 10. Download and install Apple latest bootcamp drivers, things should work normally once those drivers are installed.

Step 11. Enjoy!

For the external Windows 7 bootcamp on MacBook Air 2011 I've followed a convoluted road, as ot was a result of a gradual migration. I suspect a shorter road will work.

First, I've installed a second SSD drive on MacBook Pro 2012 early. This involved moving original Apple SSD to dvdvrom bay and MacOs installation with it. And inserting Samsung 840 Pro in the original HDD location.

Second, I've used a combination of Bootcamp assistant and Winclone to get Windows installed on that Samsung 840 Pro and occupy the whole drive. So I had 1 MacOs and 1 windows drive.

Third, I've cloned that dedicated windows drive into external OCZ Vertex 3 drive.

Forth, I've place OCZ Vertex 3 drive into the Seagate Thunderbolt Adaper, connected MacBook Air to it, booted it using ALT and luckily for me things worked!

Fifth, reinstalled Apple Bootcamp drivers to solve the device differences.

Unfortunately my memory is somewhat fuzzy, as it was a long time ago, so sorry for many missing details.

SUMMARY

I believe the key experimental finding there is that if you are using Thunderbolt drive, you can do it (once way or another). But you need to have time and dedication to get the partitioning scheme right. And have some luck (as different Apple hardware models seam to have slightly different boot preferences).

I've never had success in running Windows from external USB drive (once got very close to actually booting it, but it was blue-screening in disk.sys).