Okay, here's the deal. I just bought a 1TB external HD to use as a Time Machine backup. It works great, but it's kind of loud. I'm fine with it backing up once every hour, but for some reason about every 10 minutes or so it wakes the hard drive back up from its "sleep" mode (or whatever it enters). This causes the hard drive to make this mechanical noise that's kind of distracting. It goes back to sleep about 5 minutes later, and just keeps doing it over and over again. Why is it doing this? Why can't it just wake it back up every hour when it needs to back up? Oh, and I tried unchecking the "Put hard disks to sleep when possible" box in the Energy Saver prefs, and it did nothing. The external still goes to sleep and wakes up as it pleases. Please help!