> I just noticed that I find reports of CVC4 crashing on my Mac (running OSX Sierra now) a few times per day.
Thanks for reminding me of this. I have about 12 unanswered emails on Isabelle Users which I haven't fully processed yet and Eugene's report is probably one of them.
We will soon recompile CVC4 and other provers. We can then check if the problem has automagically gone away in the past two years of CVC4 development. I must say, I always use the repository version of Isabelle on my Mac, and I used to have many CVC4 zombies lying around (a symptom of the crash, I believe), but in the past N months things have gone quiet, so I'm wondering if something has improved on the Isabelle side.