Are you using "Clear history when Firefox closes" to clear your personal data like the cookies? *Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings Can you clear the history manually? *https://support.mozilla.org/kb/remove-recent-browsing-search-and-download-history ---- Create a new profile as a test to check if your current profile is causing the problem. 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 files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox