My experience on installing Windows 10 on external drive

There is an article spreading all over the internet teaching users how to install Windows 10 on external hard drive under a Mac, which I believe it is from 9to5mac:

How to install Windows 10 on your Mac using a “Boot Camp” external drive via Windows To Go [Video]

However, there is a serioud problem occur if you follow the article:

• It is NOT a boot camp installation although the article claims it is, it is just Windows to Go

In my case, Windows to Go has several limitations comparing to an ordinary boot camp Windows installation:

1. Sometimes the Windows fails to boot after a reboot
2. Most importantly, you can't update the Windows system easily with Windows to Go, unless you purchase additional software such as Windows to Go Upgrader, and I can't even make sure there is a successful case to upgrade Windows with this software

Therefore I found my own way to install Windows on a external hard drive with Mac, I write this not only to share my experience with others who is also interested in doing so, but to remind myself the workaround for future use.

Firstly here are the things you need:

1. An external hard drive
2. A Windows 10 iso
3. VirtualBox (free)/VMware Fusion(paid)

You can actually use a physical hard drive with VirtualBox/VMware thanks to the feature of VMDK, and that's the trick. You can create a VMDK virtual disk file linked to your hard drive, and import the VMDK into VirtualBox/VMware, then it will treat your physical hard drive as the virtual one. So every change you have done to the virtual machine is just written on the hard disk, including the installation of Windows. I don't plan to write the actual workaround as there was somebody on the Internet have done it, so just have a look on this:

https://www.serverwatch.com/server-tutorials/using-a-physical-hard-drive-with-a-virtualbox-vm.html

But there is ONE thing to note:

On a Mac, if you want to create a VMDK linked with your physical drive, or import the VMDK file into the virtual machine, you need root access to the file, so you must execute the command provided in the passage with sudo, and start VirtualBox/VMware with sudo as well.

I did not purchase a copy of VMware Fusion so I don't have the idea of how to do this in VMware, but I guess since VMDK is originally developed by VMware, VMware Fusion should have a similar or even easier way to perform the above task, and anyone's feedback regarding this is welcomed. 🙂

Remember NOT to install the virtual machine drivers on your installation, because the system you installed would be used on a Macbook eventually instead of using in a virtual machine, so just ignore any notification if it tells you to install those virtual machine additions/tools. For installing Boot Camp drivers, you can simply refer to the 9to5mac article above, this is the only part that the article is useful. :p

Now you have an ordinary Windows inside your external hard drive. You can simply boot into it, but things are not done yet, you will find that you are unable to update Windows if there is a new system update in the future.

The next thing you have to do is change the regedit of your Windows, otherwise the default configuration would prevent your Windows to perform a system update. And the workaround is here:

https://social.technet.microsoft.com/Forums/windows/en-US/9f96f44c-4c14-4a51-87c9-7123a0ad29f5/windows-to-go-windows-10-upgrade-to-anniversary-update?forum=win10itprosetup

So everything is done? Not yet if you just need to perform a system update right now.

I found that even you change the regedit configuration, the update process would still somehow be interrupted after a reboot, the screen flickers for 1 to 2 second and you will find that you are still in the previous version of Windows.

Now we need to go back to the steps of VirtualBox/VMware. Boot the system you have installed on the external hard drive in a virtual machine, just perform the update directly, this time you can finally install the update successfully.

Luckily only a system update (i.e. Creators Update) would require such steps, otherwise you can just perform minor update in MacBook under Windows.

It is never a easy task to install and maintain a Windows 10 on external hard drive with MacBook, but I think given that an external hard drive is still much cheaper than SSD, and its portability, some people would still want to install Windows 10 on it just like me. 🙂