Let me just say I've used this same Imac to setup and configure my old Harmony one. I have had the Harmony 900 for awhile and cant for the life of me figure out why I can't get this working. When I updated to the Logitech Harmony software 7.7 which I have to have for the 900 it pops up with an error. I get this message "/system/library/Extensions/AppleUSBethernetHost.kext" I have no idea what this means. This is my first remote that has a RF on it so I don't know whats going on. Help! I need to get this setup before my wife kills me she wants one remote not five.