I have this unit set up and updated to the latest DSM 4.2, my retina macbook pro running just fine (finally arrived!) but time machine is very unstable. The only way I can get time machine to backup to the NAS is to head into the web interface of the NAS, switch the time machine setting from "The Wayback Machine" to "not selected yet", clicking apply, then switching it back again. That only grants my mac a single run at it though, and it wont keep it that way. I have to keep resetting it. Otherwise, the NAS runs just fine. Time machine worked perfectly with my mac mini. Why does my rMBP seem to have such an aversion to it?