Duplicate files and folders can clutter up a user's computer, and they can wreak havoc on collaborative work. Although manually tracking down dupes is hardly practical, a number of specialized tools can handle the task.
Note: This list is also available as a photo gallery.
1: WinMergeWinMerge (Figure A) is an open source package for Windows that can find duplicate files and perform merge and comparison of various text file types. The upcoming version 3 will work on both Windows and Linux platforms. The tool can perform some advanced folder comparison, which is a great feature for developers and system administrators. And because you can run it directly from the executable file, it's useful on a desktop support tech's USB drive.
2: DoubleKillerDoubleKiller (Figure B) offers powerful comparison features, including hash comparison and filtering of which files to include in the comparison. One neat feature is the ability to compare a small number of "fresh" files against a collection of "known" files, which could be a considerable help in a team or collaborative environment. It's available as both a free version and a paid version. The paid version is substantially more useful than the free version.
3: Easy Duplicate FinderEasy Duplicate Finder (Figure C) lives up to its name, being easy to use indeed. But it also includes some advanced duplicate detection options, like MP3 tag and JPEG EXIF comparison. And it can hook into Outlook to detect duplicate emails, which can be a useful function for some. Easy Duplicate Finder is free with a restricted license (which can be upgraded), but it will look to add browser toolbars when you install it.
Easy Duplicate Finder
4: dupeGuru Music EditionDespite its name, dupeGuru Music Edition (Figure D) is not just for comparing music files. It adds the music functionality on top of a robust duplicate finding application. Using a smart filename comparison algorithm, dupeGuru Music Edition finds duplicates even when the files have different names. dupeGuru runs on Windows, OS X, and Linux. It also follows a "fairware" pricing model: You can see how many hours the developers put into the application and how many have been paid for by donations and then make a donation yourself.
dupeGuru Music Edition
5: Duplicate Images FinderDuplicate Images Finder (Figure E) is a special-purpose application that compares image files and detects duplicates based on image similarity. Now be prepared —the matching can take quite some time. But the comparisons are much more difficult than those performed by the other apps on this list. This is an excellent tool for someone who takes a ton of pictures and wants to easily find the best ones to keep or print. Duplicate Images Finder is open source.
Duplicate Images Finder
Justin James is an OutSystems MVP, architect, and developer with expertise in SaaS applications and enterprise applications.