I tried my external Blu-ray drive, which is basically a laptop drive in an enclosure (USB 3.0), and the Surface had a fit, popping up warnings about over voltages (I think that's what it was), even with the tablet power cable plugged in. I wanted to use it to burn a Windows 10 DVD (didn't have a spare USB stick at the time) for use if I do a clean install. The enclosure has a power plug, and came with a USB cable to suit, so I just plugged that into my phone charger that was next to me and it worked fine. A shame it needed the extra cable, takes away portability.