how can i back up with time-machine when i want? i backed up with it like 2 weeks ago and then turned it off. now i switched the backup drive on again and set timemachine to "on". but there's no option to force it to back up. it just says "next backup": -- ?? EDIT: oh i found it. you have to right-click on the dock icon to do "back up now". weird apple didn't include it in the timemachine system preferences.