The Verbatim 500GB hard drive with at USB3 ASUS Ultra Notbook UX31A-R4003V with USB3 interface "hangs when writing data repeatedly on". On USB2, and at a approximately 1 year old Sony Vaio notbook with USB3 works the external hard drive from Verbatim - at 2-3 attempts. Reformat brought no remedy. Apparently not "understand" the USB3 controller from ASUS notebook with the USB3 controller from the external Verbatim Hard Drive. Sometimes the message from ASUS notebook was that not "the full USB power is available", suggesting that the ext. Verbatim hard drive was operated only in "USB2 mode", but nevertheless led to hang when writing. I have therefore the ext. Given Verbatim hard drive to the supplier and asked for purchase price refund. I guess that this is not just an exemplary error.