Arduino Mega; Can't Upload

Watch out for USB 3.0 port issues !
It is a known issue but not with all USB 3.0 chipsets.

First and easiest work around is to insert a decent powered USB 2.0 HOB between the USB 3.0 port and the Arduino.
Second work around is to roll back a microsoft driver to the motherboards own driver.
Third fix is to change the USB settings in the BIOS to the middle speed compatible with USB 2.0.