Which files to delete?

Does the Duplicate File Finder only display the duplicate files or does it show all the copies of a file?

It shows all the copies (that you have specified to look for), but doesn’t let you delete them all, you have to keep at least one of the copies.

You should be careful about just what duplicates you delete, some duplicate files are needed by Windows and deleting the wrong things can result in your computer not working properly. (or even not working at all).

See this for more advice on how to safely use the Duplicate Finder: