When importing references from different databases, you may find that you have duplicate references in your EndNote library. The following steps show you how to find and remove these duplicates.
If you have a large number of duplicates and don't want to go through them one by one, you can highlight and delete all the duplicates at once. To do this, simply click Cancel in the Find Duplicates window.
The window will close, and a temporary folder named Duplicate References will be created. You will now see all the Duplicate References highlighted in green in your EndNote library.
You can now go to References > Move References to Trash to move the highlighted references.
Tip: Check for and remove duplicates as soon as you add new references to your library, before annotating and using the new references.