Have to be very careful about unplugging one device and then plugging in another. I fixed the problem of the unregonized device by shutting everything down and then disconnecting the power supply and then restarting - plugging the device in I wanted to use - my camera - then turning the device on and it recognized it _FINALLY_ and then I safetly removed the hardware properly and then I plugged in my Printer and then turned the printer on and then it recognized it too...I'm flying now.