I walked while my card was backing up, and received an error. I opened my device and discovered that it had been delivered with a Samsung disk. After replacing it with an Intel SSD that I had, I'm still not able to back up the contents of the memory card. When I try, it freezes about half way and says "Unexpected OTG error".
The SSD was formatted in the ND2700, the memory card has only been used a couple of times, and I am able to back other memory cards up.