Windows doesn’t make it easy to deal with duplicate files all by itself.
This isn’t helpful, of course, if you don’t know which files have duplicates.
Note however we’re not as fond of CCleaner as we used to be and there arebetter alternativesthese days.

Some advanced features are available at a cost, but that’s entirely optional.
Two more recommended apps for macOS users: Trend Micro’sDr.
Cleaneris free and offers a disk cleaner and big file finder.