My MacBookAir has frozen three times in the last week, each time while connected to a streaming session: twice with Facebook Live and once with Google Hangout. These are the only times I have ever used these services, and now I’m afraid to use them again. The first two sessions ended when the whole computer froze and I had to reboot the machine and give up the streaming. The third time, today with Google Hangout, half an hour into the session the screen just froze, leaving the sound operative, and oddly the mouse arrow still moved (though I couldn’t do anything with it, it wouldn’t click anything). I was able to finish listening to the lecture, though the captions and the slides also froze. I could hear an occasional beep when an email arrived! The computer is 5 years old, running Mojave. Anybody have a similar experience? Is there a way to unfreeze it without rebooting?