I have a 3TB Backup Plus. It is connected to the iMac via a 15' USB cable -> original USB cable. The 15' USB is one that is supposed to be powered (via the USB) to keep the voltage up for the distance. The issue is everytime I wake the iMac from sleep it says the drive has been improperly disconnected. I'm trying got figure out what I need to do to make this work. Any ideas?