Why is my external HD firing up and making noise when it's not on a scheduled update? Shouldn't Time Machine only access the HD every hour, do what it has to do, and then shut off till the next hour? Also, sometimes I'll right click an item in finder, go to the "Open with..." option, and the list of apps to open with will not show up, the external HD will start to rev up like it's being accessed, and then like 4 seconds later the list of apps will pop up. Maybe all of this wouldn't be so annoying if my external HD was silent. The one I have is only like 2 years old, but still it makes a noticeable amount of noise. Anyone's external HD silent? What brand?