Elements 13 Delete Duplicate Files

https://forums.adobe.com/people/adam+sigal  wrote I recommend the program called Duplicate Files Deleter, very good and safe to use, I'm sure it will help!

There are other similar programs.

The problem begins if you are using catalogs in the organizer. Remember that if you delete, rename or move files outside of the organizer, they will be shown as 'missing' and you'll have to delete them from catalog. Deleting big batches of files in the organizer takes a lot of time.

External programs do work on the files in your selected drives and folders. Those may be in the catalog or not. What does happen if the duplicate the program deletes is the one in the catalog?

The organizer offers a feature to find duplicates based on visual similarity. In practice it is often better to stack duplicates rather than spending a lot of time to decide which items to keep on various criteria.

Combining external duplicate finders with the organizer and your catalogs is possible, but you have to understand how they can work together.