There is something very wrong with EndNote 21. I am now encountering constant freezing when I import records from Scopus. The last four libraries I have created and downloaded references into have contained a reference that has caused the program to crash. This was not the case before the latest update. Please fix this.
Is it always the same reference, or varied? Have you looked at the file to see what might be triggering it - or send it to the support team at clarivate?