FInd Not duplicated files

[aloboa]

Feature Description
Given the scenario in which I normallly copy files from a drive (eg an SD) to another drive (eg hard drive) and then organize the copied files in different directories, I need to find those files in the SD that have not been copied to the hard drive before I actually clean up all files in the SD. Alternatively, delete from the SD those files that have also been found on the hard drive.
As far as I understand, the SD would be the folder to Search and the hard drive would be the reference directory, with recursivity in both cases, but I would need to search for not duplicated. Is this possible?

I could also use czkawka to delete files in the SD, but the output includes those in the hard drive, and manual selection would be tedious. Also, Sort by folder cannot be used (see #1266). Best would be having different lists for Search and Reference folders.

[PJDude]

You may try dude. Non-duplicate files are visible in the bottom panel.

[aloboa]

You may try dude. Non-duplicate files are visible in the bottom panel.

Yes!
Thanks

[bonderado]

This is a bit late, but ...
in your screenshot, you marked "/media/alobo/PortableSSD/Islandia" as the reference folder.
Assuming that is indeed your hard drive, if you use the Select > Select all button at the bottom of the duplicates list, will select all files that are not in the reference, that is, all the duplicateds present in "/media/alobo/LUMIX/DCIM", tha you can then delete.