I just picked up an used MBA. The previous owner reinstalled Mountain Lion and everything seems wiped off the machine. But when I go to "About This Mac" and storage, it shows that movies take up 30 gigs, music 10 gigs, apps 10 gigs but these are nowhere to be found on the machine. In Finder, if I do a search for movies nothing comes up. As far as I can tell, there is only one user on this machine. Is there a way to locate these lost files that are taking up space?