I’ve owned my desktop PC for a little over 3 years, and most days I’m scared to look into my folders to see what I’ve been hoarding. Wading through thousands of pictures, Word documents and PDF’s to “trim the fat” is not something I look forward to. A recently discovered free program, however, has taken that task and made it completely possible.

PC Magazine was the first to introduce me to the wonders of the Double Killer app. Free for download at several locations, I went directly to the official site to get my limited copy. This .zip file took little time to download, and I was running in no time. What’s it do? Everything I imagined, and more!

By selecting the folder I want to target, Double Killer scans for files that are similar in name, size, date, and CRC32 Checksum (think unique fingerprint.) Each of these scan criteria are optional, and I had best results with size and CRC32 checksum (which appear to be the default.)

Once the scan is complete, a list of all files with duplicates are listed (each grouped with it’s “twin”), and you have the option to go through them one by one, or just select all of the duplicates and trash them. It is recommended that you either select “Check first dupes” or “Check last dupes” but NEVER both! This could get rid of all copies of the file – not what we are intending. The same undesirable outcome will happen if you select “Check all.” Once you have selected the stuff you want gone, you can choose to send them to a new folder for careful review later (recommended) or delete them permanently. The premium version is $19.99 and allows you to send to a recycle bin, instead.

My first scan rid my Documents folders of over 1106 duplicate files and a 103,801 kb of unnecessary junk. My Pictures folder had even more garbage – hundreds of duplicate pictures that I downloaded without deleting from my digital camera more than one or two times. And since my FireFox browser is set to put a copy of all downloads directly on my Desktop, I had more duplicate installation files and application shortcuts than one girl should ever have! This cleaned it up in less than a minute!

Double Killer can mess things up if you’re not sure what you’re doing, but the included help index covers it fairly well. If you’re wanting to use the application for commercial purposes, you’ll need to spring for the full version. For one private workstation, however, this is one free app I’ll use often.

(I have also heard rumblings of some fantastic Open Source versions of a duplicate file scanner, but I haven’t tried them personally. For a good listing of OS options, visit SourceForge and search for "duplicate files".)