This isn't a review, but a comment. "DupeZap" (which I have not used) and "TidyUp" (which I have) are from the same developer, Hyperbolic Software. (I have recently reviewed "TidyUp" favorably on MacUpdate.) It's not exactly clear what the difference between the two is, although "TidyUp," which costs $10 more, is described as a "must have for pro users." From the company's marketing standpoint, it might be helpful to more specifically delineate their differences. The developer is EXTREMELY RESPONSIVE to comments and inquiries, and has always replied to me personally and promptly. Note his reply below (under the name "Giuseppegiu") from 5/29/12. He has been perfecting his products for years, obviously takes great pride in them, and you get the sense that he's a meticulous software engineer. World class software and support -- a model for the industry.