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Free up disk space with Mac app Duplicate Zapper

Root out duplicate files to reclaim precious hard-drive space on your Mac.

Screenshot by Matt Elliott/CNET

One of the chief culprits behind a slow Mac is a cluttered hard drive. If your Mac's hard drive is nearing capacity, it's time to take action. I have offered a handful of tips about how to clean and speed up your Mac, but here's another: Mac app Duplicate Zapper.

Duplicate Zapper is currently discounted at $1.99 as part of $2 Tuesday in the US (£1.49 in the UK and AU$2.49 in Australia). Once installed, the app offers six sliders to narrow your duplicate hunt. Because I like to think I keep my music, movies, and pictures in some semblance of order, I chose three types: Folders, Archives, and Documents.

Next, Duplicate Zapper asks you to name locations to include and exclude from your search. I simply selected my Macintosh HD so it would scan everything.

Screenshot by Matt Elliott/CNET

When you have your locations set, click the big green Scan button and Duplicate Zapper will begin its scan. It took about 12 minutes to scan my hard drive. When it finishes the scan, the app shows you a list of duplicates it found. Next to each file in the list are two numbers: the number on the right is the total number of copies found, and the number on the left is the number you have selected to delete. You can manually select each file on the list and then check out a preview of each of the copies to verify that they are, indeed, duplicates. If you hover over a file in the right panel, you can view its location, and clicking on the magnifying-glass icon opens Finder.

Going manually through the list, file by file, can be time consuming. Thankfully, Duplicate Zapper offers a number of preset selections. From the drop-down menu at the top labeled Auto Select, you can choose to a method for choosing which files to keep and which to trash. Your choices include keeping the earliest files, keeping the latest files, keep those with the shortest or longest path, or keeping the originals. Below the Auto Select options is a drop-down menu for sorting your list of files.

Screenshot by Matt Elliott/CNET

With my first scan, I reclaimed 1.55GB of hard drive space. Not bad for roughly 15 minutes of work. The developer states on the app's page in the Mac App Store that Duplicate Zapper "will never scan important system or application files, ensuring your Mac stays safe."