I have a I mac Running tiger This is the third time this has happened. The computer will not go into sleep mode . The support people have had me remove the system config from the library and put it into the trash. This works until the next time it happens?? When I down load updates it happens.. : when I shut down for one or two days it may happen SO is there something I can do to stop this ? why would it happen at all? I don' want to wait till I am dead in the water and have to pack up and travel 200km to sudbury thanks Barry