I have had an external drive setup for 100% by Time Machine. I have set the time for backups using the Time Machine Editor to every 4 hours. I have the energy saving setting to spin down drives. The problem I am having is my Firewire ext drive spins down, idles for a few and then spins back up. I can't seem to determine what is causing it to spin back up. Is there another setting I need to adjust so the drive can rest?