The external hard drive is working properly (about 150 MB / sec) with a key M4 in. As against the supplied USB cable does not work properly (there is a loose connection in) so the computer sees the hdd and seen more ... It's impossible to make a copy with the original cable. I price a cable that was supplied with a Western digital My Passport (USB3) and everything is perfect. It's just a pity that the cable supplied is not good.