I have two Series4 dual-tuner Premiere units - I'll call them A and B. Each has a digital cable card and they are both wired into my home network. A has a MyBook DVR Expander attached. When I start to transfer a recording from B to A, within two or three minutes A will hang. I've only tried to transfer HD recordings, and I've only tried from B to A, not the other direction. A hangs whether I'm transferring the recording for later viewing, or watching it while it transfers. I have to pull/reseat the plug to reboot it. When it reboots, sometimes the video is choppy and the unit is dog-slow for a minute or two, then it reboots again on its own. This may happen one or two times until it boots up and works fine. I suspected the hard drive, so I booted it into diagnostic mode and ran SMART hard drive tests which took all night but passed with no errors. I have no problems if I don't try to transfer recordings, but I want to be able to! What might be wrong?