Hi there,
am I not understanding how the smart group “Duplicates” work?
In this group I find ALL instances of a file, this is the original file and the duplicate.
What use is such a group?
Best, Matze
What else would you expect it to display? 
As I explained in the similiar older topic: ONLY the item, that was duplicated, as the rule “Item is duplicated” suggests.
A duplicated item logically has two instances. The original and the duplicate. Each is a duplicate of the other, therefore they are both listed.
This is not what “item is duplicated” says. It should be “item is a duplicate”. Because: First you have the original, which is duplicated. It makes the original and the 2nd version to duplicates of one another. But only the 1st is duplicated.
“item is a duplicate” would still return the same results as both files have a duplicate state.
This is also why they are both marked with a duplicate property icon or listed with their names in blue.
Generating a duplicate manually confers no more importance on either file. One could just as easily want to delete the first as the second. If only the second file was marked as a duplicate and showed up in the smart group, how would you easily find and remove the first file?
But then I wouldn’t ask myself why the duplicated file AND the duplicate are listed. Although semantically it is still not quite exact.
A duplicate is a copy taken from the original which is the duplicated.
I want to use the smart group duplicates to automatically trash duplicates. It can not be used fot this purpose.
A duplicate is a copy taken from the original which is the duplicated.
This is a textbook definition but not necessarily a practical one. As I said, one might want to preserve the second file and remove the first. Since both have a duplicate state they both appear in the smart group and you can choose which item you’d like to delete. Sort by Date Created if you want to determine which is the older of the two.
Thanks for the hint. The trash duplicates Script works fine, though not automated.
As a Softwarepublisher you might want to try to think as a Softwareuser once in a while: Some of them understand the “textbook definition” of words and not the “nerdbook definition” 
