I recently upgrade a Dell E1505n from 8.04 to 10.04. I had to reload the home directories from backup media. For whatever reason when I select Edit>Preferences, Firefox shuts down/crashes. I renamed the default user directory and profiles.ini file; and then let another profile be created. Every thing worked fine. When I went back to the old profile, Firefox still crashed.

Anyone have ideas of why this is occurring and what files I need to work with to correct the issue?