This should be simple enough, but proved to be a little tricky. Step 1: Get the Thunderbolt drive to work under your Bootcamp Windows 7 installation. Plus several free downloads from the internet, see description below. Lacie Rugged USB 3/Thunderbolt series, 120GB Solid State Drive MacBook Pro 15' Retina Display (mid 2012), 2,3 GHz Intel Core i7, 8GB RAM, 250GB SSD Most reports claiming to have successfully been able to run Windows 7 from an external drive, had used Thunderbolt drives, so I decided to get myself a Lacie Rugged USB 3/Thunderbolt series Solid State Drive. I was very close to success with this USB 3 drive, but Windows would fail during start-up. I had a HDD in a USB 3 enclosure, and first tried to install Windows to this (using various guides on the web). I'd read many conflicting reports on the web, some claiming they'd done it successfully, while others said it would be impossible, because Windows 7 wouldn't run from an external drive.
I don't use Windows that often and for that reason, I wanted to move the Bootcamp partition to an external hard drive, freeing up space for the Mac side on the internal SSD.
I needed to install new software in Windows, but was running out of space fast and didn't have the necessary space on the Windows side. Due to the relatively small, non-exchangable SSD on my Mac, I'd limited the bootcamp partition to 50GB when installing Windows.
