Paired with Dr. Cleaner, makes for a nice inexpensive cleaner

This isnt some hardcore cleaning app that will let you set all sorts of parameters to define what constitutes a "duplicate". It just searches your HD for bit-perfect dupes (maybe uses a hash of the file, Im not sure). Then you can review and delete the dupes, should you choose. Its pretty safe if you pay attention, which you should ALWAYS do....even the most expensive apps cant do your thinking for you. Maybe you have songs in your iTunes database as well as in a separate external library youve organized meticulously. Obviously youre going to want to keep both. But for lots of files, you can safely zap them. Just be organized in the first place and deliberate when you use tools of mass deletion and all will go well. I especially like that this (50% off right now, cha-ching) integrates seamlessly with the free Dr. Cleaner, also from Trend Micro, and provides an easy taskbar icon way to both free up memory, delete junk files, and (with this), free up hard drive space by identifying and cleaning up dupes. With all the cloud drives and mobile devices that sync with our Macs these days, Id be really suprised if you DIDNT have a lot of dupes, especially when it comes to photos! Anyway, stop listening to me and just buy the thing. Its handy and you wont regret it, nor will it do anything annoying to get in your way. Just remember, it isnt a PRO tool so dont expect it to have the robust features of one.

Stageon about Duplicate Finder - File Clean