You could have downloaded Keep One 7.0 from our software library for free. The most popular version among Keep One users is 7.0. The software belongs to System Utilities. This free software is a product of Bobbing Software.
From the developer:
Drag and drop folders or files into the Keep One window. Keep One is very careful to always "keep one" of the duplicate files. You don't have to wait for Keep One to finish "processing" files. You can drag-and-drop more files, or start removing duplicates as soon as they are found. Keep One finds files which are exact copies of each other, and displays groups of these duplicate files.