EndNote X8 Keeps Crashing on Mac

Likewise, I’ve been having this problem for months - multiple crashes during different actions. Running Endnote X7.7.1 on Mac Air 10.12.5. I had this problem on my previous OS also. 

Has anyone had any experience using Mendeley or other programs with Mac successfully? I like(d) Endnote but it’s impossible to work with. Thanks.