Hi Dan,

The Duplicate Finder can search for files with the same File Name, Size, Modified Date and Content; however it isn’t able to determine which files are needed and which can be safely deleted.

You can open a file from the Duplicate Finder screen by right clicking the file > Open Containing Folder, then double clicking the file in the window that opens.

When you are searching it in the search Window, what is the location in which you are searching it. If it is a Drive (Like D, E, etc), the file would be searched only in that particular Drive or folder and not anywhere else. Whereas, it might be possible that the duplicate file is present in any other location other than the one you are searching.

So, you need to search it in the Full Computer instead. Also, you can try the advanced search as if the file is in hidden mode, it might not be searched automatically within the basic search. 

It is normally safe to delete duplicates of your personal pictures or films, but as before ensure that you verify the file path and the content of the files before deletion.

I hope this helps.

Regards,
Lokesh