With your choices made, click Next. A list of all the selected-to-delete files appears, so you can verify your selections. Once you've done so, click Clean, and those duplicates are moved to the Trash. The Trash isn't emptied, however, so you're welcome to check it one final time before you finally delete the files within (by manually emptying the Trash).
Bare bones though it is, Duplicate Detective offers a couple of customization options. Within its Preferences window, you can exclude certain folders from the app's scans. For example, if you're concerned that you might lose an important image, you can exclude your Pictures folder. (Note that Duplicate Detective won't scan the contents of a package, such as an installer or your iPhoto Library, unless you manually open the library package and specifically drag one of the enclosed folders to Duplicate Detective for scanning.) You can also tell the utility to skip files that bear a particular file extension — .key, for instance, to lay off any Keynote presentations you've created.
But that's about as fine-grain as Duplicate Detective gets. Other utilities, such as Hyperbolic Software's $30 Tidy Up, offer scads of customization options and can search not only for exact duplicates, but also similar files — for example, Tidy Up can look for .mp3 and .aac versions of the same audio track. And you may find value in each approach — one app to easily remove exact duplicates, and another when you want to really dig in and find those "this is darned close to that" files. But for quick-and-easy duplicate finding, Duplicate Detective is a nice tool to have on hand.
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