Much as I am chagrined to say it: Sherlock sucks. Any search app that can't search every directory on my drive, even those scary system dir's, is half a search app. Thankfully there's an alternative: the 'locate' command. All you have to do is open a terminal and.... err, nevermind. Just download Locator and use its dandy GUI (using locate is also a hell of a lot faster than using Sherlock. Sure, there are no pretty graphics....).