I have around 200 references for different things i am working on. I am trying to categorise them by topic. So I make a group and copied/pasted references into there. But now in the ‘all references’ section, there are duplicates of the references I had copied to paste into the group file (even though the references I copied and paste did successfully end up in their group folder). Why is this happening with the duplicates in the all references? I just want to organize my references into groups based on for each manuscript i am working on. Is there any way I can do this better?
You can, or you could add a keyword and create a smart group based on that keyword (or any other field).
As an alternative, if your endnote version creates a group when you are editing a paper, you can DRAG them to a new group and when the number in that temporary group is more than the number in your new group, drag them again (it will add just the new ones).