I have been unplugging external HDs when I run a software update as I heard the update may cause problems with those external HDs. Usually I just unplug the entire firewire hubs. I have two questions: 1. does it cause problems with updating if I kept the USB hub (which connects RF mouse and keyboard) during the updates? 2. should I unplug ACD while running updates? I run my PBs in the clamshell mode and I would rather run those updates with the UPB hub in place (as I need the input method to log in).