Hello. i have an external hd connected to my MacBook Pro. And every so often it turns on for no reason. I will start searching spotlight, and it starts spinning. I have even excluded the HD from spotlight, and it still does it. I could even open iPhoto or iMovie and it just starts spinning. Not all the time, of course. I use the external mostly for my iTunes music if that helps. Is there anyway to turn off the external until i actually read data from it?