I have a MacBook Pro (Retina, 15-inch, Mid 2014) - Yosemite 10.10.1, and am using Boot Camp Assistant to install Windows 7 Home Premium. However, I can't for the life of me get the Mac to recognize/boot from the USB drive. Here's what I've done: Macbook Pro Retina - Yosemite 10.10.1 1. Used Boot Camp Assistant to "Create a Windows 7 install disk" and "Install Windows 7". I downloaded a Windows 7 Home Premium x64 .iso from Digital River (file name is X17-58997.iso). 2. I'm installing on a 32GB Sandisk Ultra Fit USB drive. 3. Installation works fine and finishes. 4. System restarts, but throws "Non-system disk - Press any key to reboot" error. (interestingly, hitting a key does nothing on this screen). 5. So, I force reboot, and it then throws a "No bootable device -- insert disk and press any key" error. 6. So, I force reboot again, while holding option, and my only choice is my main "Macintosh HD" drive - it does not show the USB drive as an option. So, I boot as usual. 7. Then, I check System Preferences > Startup Disk, and the USB drive is not available there either. Why is this happening? I've also attached a few screenshots of the USB drive. I've read that the USB drive needs to be formatted in ways other than MS-DOS, but that's what Bootcamp Assistant is choosing for me, and the process continues no problem.. Also, it seems as though the contents on the USB drive look fine. Thoughts?