Free programs find and remove duplicate files

It doesn't take long for a computer to collect duplicate copies of all sorts of files. When my year-old laptop started running low on disk space, I knew one of the fastest ways to recover some lost hard-disk storage was to give the machine's duplicate files the boot. If you rely on the file-management tools in Windows to root out unnecessary, space-clogging files, you're in for a long day of folder hopping.

Several free utilities promise to hasten the file-cleanup process. The two I tried — Duplicate File Finder from Auslogics and Digital Volcano's Duplicate Cleaner — take very different approaches to dupe removal. Duplicate File Finder features a clear interface and speedy operation, while Duplicate Cleaner identifies more types of doubled-up files but is trickier to use, which means you're more likely to delete a file your system needs.

Fast and friendly way to spot file copies
There's a lot to like about simple software — especially simple utilities such as Auslogics' Duplicate File Finder. The program presents a sequence of dialogs for choosing the folders to scan for duplicates and the categories of files to include (such as images, video, audio, or everything). Unfortunately, you can't limit the search to specific file types. Other matching criteria include file name, date, size, and contents.

The program's default is set to ignore files smaller than 1MB. When I used the default settings to search for duplicate files on a complete 50GB Windows 7 setup installed on an 80GB disk partition, fewer than 50MB of dupes were identified. On an 80GB Vista installation (on a 180GB partition) with the file-size limit disabled, Duplicate File Finder reported many more file multiples, but only 97MB of storage space would be recovered. All the scans were completed in about a minute, and searches for specific categories of dupes were completed in seconds. Note that I didn't test the content-search option, which promises to be slower.

Taking a closer look at your file duplicates
Digital Volcano's Duplicate Cleaner has many more rough edges than Auslogics' dupe IDer, but the program turns up more duplicate files — including DLLs and other system files. Unfortunately, you aren't given much guidance on the files that are safe to remove and those whose absence would be noticed.

The first of the four tabs across the top of the program's main window is used to select the folders and file criteria to search for. Like the Auslogic product, you can't choose specific file types to scan, but its search categories include images, music, movies, and Office documents.

You can use Duplicate Cleaner's Selection Assistant to search for a single file type or specific file paths, along with such search criteria as oldest or newest, largest or smallest, or all but one in each group. A nice option is the ability to select a single folder path and remove all copies of that folder's files in all other locations.

After making your selections, click the Go button to begin the scan. It took several minutes to scan the 80GB Vista installation, but hundreds more duplicate files were discovered, and they were using up nearly 500MB of memory. The duplicates included dozens of system files, executable files, and log files.

I'm generally cautious when it comes to deleting files that Windows or some program or device may need. I was satisfied with the space I saved sticking to program's options for spotting duplicate media and other data files.

While I preferred Duplicate File Finder's straightforward and relatively safe approach to finding and removing duplicate files, the more-thorough scans conducted by Duplicate Cleaner promise to recover more lost storage. If you're looking to squeeze a little more life out of an overcrowded hard drive, those extra megabytes could make the difference.