Hello forum, I have a Mac Mini with two external WD MyBook's attached. The drive in question, is configured for Time Machine backups every four hours. It should sleep the rest of the time. But every once in a while, it wakes. I just revs up for no reason, then after a short while it goes back to sleep. It can happen when I open a folder, open a file, click a link in the browser or some other seemingly unrelated action. I tried to untick the "Put the hard disk(s) to sleep when possible" to see if I then at least could get the drive to stay awake instead. This did not change the behavior at all. Does anybody have a clue what I can do, to get OS X to leave that drive the hell alone, other than Time Machine??