After upgrading to Windows 10 (ISO upgrade) When I power up my Surface Pro 3 and the USB 3 cable is attached, the PC boots to a white screen and locks. If I remove the USB 3 cable before the boot and replace it afterwards, everything works fine. I have one monitor, a mouse and a portable HD running of the UD3900. All work fine if the USB3 cable is plugged into the PC after it boots up.
According to MS I have all the latest firmware and updates installed. I ran the pluggable clean utility and installed the latest drivers. No change no matter what I do