Symptom
When watching a slide show in iPhoto, the slide show stops and the computer stops responding ("freezes").
Solution
If the computer stops responding during the slide show:
1. Press the Command-Option-Esc keyboard shortcut to open the Force Quit window.
2. Select iPhoto from the list of applications.
3. Click Force Quit.
4. Click Force Quit again to confirm. iPhoto quits.
If the computer does not respond to the Force Quit command, press and hold the power button on the computer to shut it down.
To resolve this issue, update to Mac OS X 10.2.3.