Hi,
I am having a similar problem to serotonin in that when I plug a USB 3.0 drive in to my NUC D54250WYK it powers on even though the NUC unit is switched off (but plugged in to the mains). This seems to be causing me a bigger issue though in that when I boot in to Windows 8.1 the drive is not recognised until I unplug the drive and plug it back in again . Are these issues related or is it likely to be something else?
I have updated to the latest Firmware.
Many thanks!