I found that Smart Groups are kept current via a background process. Unfortunately, if you have a lot of Smart Groups and references, then this can kill performance as happened to me (and I’m unable to use Smart Groups as a result).
I don’t know why this has been implemented this way. Surely any Smart Groups could be updated whenever a reference is added to EndNote instead, and as a Smart Group is created?
An equally-plausible solution is to have an explicit user action for Smart Groups to be updated, knowing that this may take a while - but is something that could be run (once) overnight, for example.
Cheers,
- Pete