Hi,
I had to sign up to share my excitement!
For reasons that are boring, but based on merging multiple libraries multiple times, our final EndNote library contains >13k references. Some are duplicates, of course, and those are fairly easy to find. But some references also contain the same PDF attached several times (2-3x).
I stumbled on this simple to trick to find references that have multiple attachments:
In Search, select {File Attachments} contains
Then under Options, insert a Carriage Return to the search field.
Voilá! The search result contains a list of references with more than 1 attachment. I don’t know why. But it works. Sorry if this is known to many, but I couldn’t find a method for this when googling.