Be very careful as the whole concept of "a duplicate" is complicated.
A true duplicate has the same Name, File Size and even File Date.
On Windows, a drag-n-drop COPY will create this kind of pure-duplicate.
On a Mac, a COPY changes the new file's date to the moment of the copy.
Then there's a question on Links (aka Short-cuts, aliases).
Both Windows and Mac append a new extension to the file name for Soft Links(Unix/Linux term)
so it's obvious which is the original.
However, BOTH Windows and Mac also support Hard Links too, and this is were duplicates get real complicated.
Most users never run into Hard Links and this becomes moot, but if you do have Hard Links, it's even hard to tell!
A Hard Link makes an entry in the file name table and then points to all the data sectors in the original file.
Thus there's TWO Names --> same set of data sectors. Now is this a duplicate? Before you guess, be it known
that either file name, the original or the Hard Link, can be opened for write/update and the changes will be
seen in the other. So an original/Hard-Link is actually ONE FILE, not a dupicate!
So what? Guess what happens if you delete the Hard-Link? YEP, BOTH FILES disappear!
I have yet to find a tool that properly understands Hard-Links!