I've spent the last couple of days trying to get this working without success. As I have an SSD in my Macbook Air space is at a premium, and I don't want to waste it on a Windows partition I'll only occasionally use. So I've bought a decent quality Sandisk 64GB USB 3.0 drive that I want to install Windows to go on. I've found dozens of conflicting guides and opinions on the matter, but still no joy getting it working so was hoping somebody here can help. So far I've tried: Windows 8.1 To Go - won't boot at all. I've read conflicting reports that Windows 8.1 will or won't boot from a 'removable' USB drive. Windows 8 To Go - works fine on a MBP 2012 I have at my office, but refuses to boot on my MBA. It gets to the Windows logo/loading icon, but then shows a blue screen saying there's a problem and it reboots. I have tried all the various online tips such as installing the Bootcamp drivers via dism, even creating a 'hidden' EFI partition etc, but can't get anything to work. The only thing I can get to 'boot' on my MBA is a Windows 8.1 installer I made using Bootcamp, so it looks like the MBA can indeed boot Windows, but this particular method is no use as you can't install on a removable drive from the Bootcamp installer. Can anybody put me out of my misery? Or confirm it works on their MBA so I don't give up all hope?