I've had my SP4 since shortly after initial product launch. And since day 1, devices connected either via the SP4 USB port or even the dock USB ports, have always been unstable. The connection works and then disconnects and comes back again, back and forth. But pretty much to a point of the USB devices being useless with the SP4. I've got other machines, so this has never been a major issue for me. I just use my other machines for things like CD/DVD and other USB device needs. But has anyone else noticed USB device connection stability issues with their SP4? It really surprises me, that the issues are with both the SP4 USB port and even the dock's USB ports. My mouse and keyboard work fine with the dock's USB ports. But everything else, such as CD/DVD player, card readers and portable storage devices, all have issues with all USB connections to my SP4, either via the device its self or the docking station. And since those same USB devices work fine with my other machines, I know they're not faulty.