Hi, I've got a 13" TouchBar MacBook Pro, and just this morning when I connect a External Hard Drive over USB, my WiFi seems to be unusable? It slows down and has on at least one occasion, disconnected from the WiFi altogether? I've so far only tried the left hand back USB-C port, and I am using a 3rd Party USB-A to USB-C adapter. Haven't had a chance to try the official Apple adapter yet. I remember reading about this happening when people first got their MPB's, but I don't recall if it was ever fixed or not? I have the latest Release version of Sierra - 10.12.2 Cheers Stewart Edit - Only seems to be when I use my 3rd Party NoNDA adapter.