When space runs low, many users prefer the brute force route of adding additional drives, but considering the sharp price changes we've seen in recent months (courtesy of a certain annoying virus), it's logical to postpone that investment and try to be a bit more efficient with what we have. That includes detecting and deleting duplicate files we've completely forgotten about. The AllDup application will help you with that task.

Even if you perform strict system maintenance, you're likely to lose sight of several gigabytes on your storage drives. One of the main recommendations is to use applications like WinDirStat, SpaceSniffer, or a direct equivalent. But it's also a good idea to keep a close eye on duplicate files. We've repeated to the point of exhaustion that redundancy is a fundamental resource to defend against data loss, but the truth is (except in extreme cases) we don't need half a dozen copies. That's where the AllDup tool by Michael Thummerer comes in.

AllDup: Find and delete duplicate files

At first glance, AllDup can be a bit intimidating, but once you assimilate its options, you'll be very precise with your search conditions. In the "Source Folders" section you can select isolated folders or entire drives. "Search Criteria" is where the most advanced values are stored, with entries for name, extension, size, content, modification, creation, and attributes. In general terms, the first four options combined with a 160-bit SHA-1 comparison are more than enough to avoid thousands of false positives.

How to detect and delete duplicate files with AllDup
Everything starts by choosing folders and drives

"Search Options" includes confirmation requests for filters, dimension detection when dealing with images (the search is slower with that function activated), identification of parameters in audio files (bit rate, sample rate), and more. "Compressed Files" allows AllDup to analyze the contents of zip, rar, and other formats, and both "File Filter" and "Folder Filter" serve to include or exclude folders and extensions. Personally, I left the folder filter intact but added "*.exe" in inclusive mode to detect any installer I might have forgotten.

How to detect and delete duplicate files with AllDup
The criteria are your allies, don't forget to use them
How to detect and delete duplicate files with AllDup
Sometimes I forget installers. Many installers...
How to detect and delete duplicate files with AllDup
About two gigabytes to study, and why not, delete

I must admit that AllDup is much faster than I expected, but I'm also obliged to mention that my test system only has solid-state drives. In essence, more than 1,200 duplicates demanded my attention, about two gigabytes on average. It doesn't seem like much, but it's a system with only a few months of use. Imagine the number of duplicates that can accumulate over several years...

(Editor's note: AllDup offers a portable edition and has partial Spanish translation)

Official site and download: Click here