Reinstalling Firefox won't help if there are problems with the Firefox Profile Folder unless you would choose to remove personal data. Removing personal data will remove all Firefox profile folders, so you may want to backup that data if you choose to do this. *http://kb.mozillazine.org/Profile_backup *https://support.mozilla.org/kb/Backing+up+your+information ---- Create a new profile as a test to check if your current profile is causing the problems. See "Creating a profile": *https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles *http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox