If you do this: 1). OSX 10.8 Mountain Lion (10.8.2, actually) 2). Office 2011 Powerpoint 3). Laptop (Macbook Pro 15", in this case. Not sure if this is necessary, but is probably most likely) 4). DUAL DISPLAY system, with the external monitor set as "primary" (i.e. the menu bar is on the external monitor) 5). Presentation mode (where the secondary screen displays notes, timer, etc) = CRAZY FLICKER. FIXES: 1. If you "swap displays" -- i.e. make the built-in monitor display the slides, and the external monitor display the "notes" -- mid presentation, it stops. 2. If you switch the "primary" display to the main, built-in display, and THEN presentation mode, no flicker. Even if you display the actual presentation on the external monitor (and the notes on the built-in), just like before. *** Could someone else with close to the above setup test this out, and let me know if I'm the only person this happens to? (Google returns a number of hits, but just to be sure) Thanks!