Are there Instructions for the Duplicate File Cleaner? I have way too many Duplicate Files in Windows 10 Downloads.
here; http://www.piriform.com/docs/ccleaner/using-ccleaner/finding-duplicate-files
the program will find them for you, but only you would truly know which ones can be deleted.
if you are unsure, back them up first.
or if you are really unsure, unless space is critical, leave them alone.