When all is said and done only you can decide which files you want to keep and which you don't.
Nobody else can make that decision for you, and certainly an application can't do it for you.
Duplicate Finder is a powerful search tool if used right, but like any tool you have to learn to use it and use it carefully.
You are going the right way to start with, you just need to do a bit more.
As you say you should leave the system files alone, always set duplicate finder to ignore them. (unless you have a specific problem with some system files).
In fact if you don't know just (exactly) what <u><em>any</em></u> duplicate file found is then it's best to leave it alone.
Only delete something if you are certain that you don't need/want it.
In your case you say that it is accidentally copied/duplicated music and photo files that you are looking for, so there are a few things you can do to narrow that search down.
To start with as they have been copied from the same place then any such accidental duplicates will have the same file formats and the same names. (unless you did something to change them during the copying).
So when setting up the search path set it to look only for music filetypes.
Those will typically be .mp3 or .mp4 files, but there are other possibilities. <a href="https://www.canto.com/blog/audio-file-types/" ipsnoembed="true" rel="external nofollow">https://www.canto.com/blog/audio-file-types/</a>
Let's say your music files are either .mp3 files or mp4 files.
Use the 'Add' button to set the search path and filetypes. (Use 'Browse' to set the Drive/Folder).
The below would set the search path to search for .mp3 and .mp4 duplicates in any subfolder of drive 'C'. (I've done both types at the same time here, but you could do one type at once).
![image.png]()
Then set the Match by and Ignore like this - this tells it to search all of drive 'C' and only find duplicate .mp3 files with the same name and the same contents, or duplicate .mp4 files with the same name and the same contents.
![image.png]()
So clicking on search would look in all subfolders on the 'C' drive for all .mp3 or .mp4 files that have the same name and the same contents.
Note. You could search on name only and not contents, but then you should be doubly careful of the results - just because 2 files in different folders have the same name doesn't mean they are the same.
But again - once it has found those duplicates for you then you still have to decide which ones you want to keep or not, only you can know that.
The first question I would ask there is what app are you using to play your music, open that app and see what folder it is looking to play the music from.
(Normally that would be 'C;\users\<em>{username}</em>\music' but it could have been set to something else if you store your music elsewhere).
Whatever that folder is then that's probably the one with the files that you want to keep.
As you say you think there are also accidentally duplicated photos then once you have done the music files you would do the same kind of search but using whatever image file extension you normally use.
If none of the above helps then if you could let us know the full pathnames of any 2 files that you are certain are duplicates we should be able to suggest how to search for them.
(Preferably 2 of the music duplicates and 2 of the photo duplicates)