"Help us Help You" up the top of each DUC web page. Do the standard troubleshooting steps there, trash prefs, etc. You should be doing that stuff automatically. Use the Pete Gates PT Prefs utility to help trash stuff.
http://petegates.com/pg-pt-prefs.html
Does it only happen with one session, or sessions all derived from one session if so suspect that's corrupted. Try save session in create new session and import content or roll back to your last good backup.
Pro Tools exact version? System info, how much memory? How much Pro Tools disk cache do you have configured if that's supported in your version.
The program crashes how exactly? What exactly do you see on the screen. Any error messages? (ugh Pro Tools 12 you may not have a human readable log file).