I can only guess that the dock's firmware expects a very fast response, and shuts down the read process if it does not get it. Maybe it insists on USB3 speeds? Basically IDK, I'm reporting raw data. It would be nice if my experimentation (or playing around if you prefer) was repeated by several others, on other 701s. What I saw was that, using the generic cards, the read process would start then abort after ~2MB. Seemed to vary between cards. That would cause ES File Explorer to freeze also. For my purposes the solution is clear: make sure my cameras all have good fast cards in them, as that is what I use the card reader for. I suspect I'm not alone there, but again IDK.