Just to add more info. Was also caught off-guard in the middle of a presentation at a podium away from laptop on the 23rd. I was lax in updates and updated 14.3.1 and 14.3.2 on Thursday. Never had any problems previously and found Powerpoint presentation
mode locked up every 18 to 18:30 minutes. Could not even use the exit icon -- had to force shut down lap top and re-boot. Spent Sunday morning re-creating problem with laptop standalone on a table -- wireless off, all other applications off, powerpoint in
presenter mode, no projector. Locked up every 18-18:45 minutes regardless of varied idle times. Did discover that left/right arrow keys worked with mouse but still could not exit program with <esc> or <X exit> keys. Had to force re-boot of laptop which
is a 6 month old, dual core, non-retina, Macbook Air 13".
Thank you all for posting problems and work-arounds. I think I'll try reloading Office for Mac and stop at the 14.2.3 update so next week goes better. Maybe even purchase Key-note.