I tested with an old LinkSys 24-port gigabit switch yesterday. No problems at all. So in our case it's definitely a combination of the Roamio and a "green" switch. I am tempted to try and find a "green" 10/100 switch to determine whether it's related to the use of a gigabit port. I wish Margret would chip in to let us know if TiVo is actually looking in to this issue - I am spending way too much time on this.