Just bought a My Book essential. Hooked it up to my iMac. Working fine but was wondering if there was some way to back up all of the data on the mac? It seems to only want to back up the data on the user that i am logged into at the time. It is a pain to have to log into each user and back up their data. I was hoping someone could tell me how to just do a single back up of entire data all users?