Did you refresh (reset) Firefox during your update and created a new profile? This could happen if Firefox reported that it was starting slowly. When you refresh/reset Firefox then a new profile is created and some personal data (bookmarks, history, cookies, passwords, form data) is automatically imported. The current profile folder will be moved to an "Old Firefox Data" folder on the desktop. Installed extensions and other customizations (toolbars, prefs) that you have made are lost and need to be redone. It is possible to recover data from the "Old Firefox Data" folder on the desktop, but be cautious not to copy corrupted files to avoid carrying over problems. *https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox ---- * bookmarks and history: places.sqlite and the backups in the bookmarkbackups folder * other SQLite files like cookies.sqlite (Cookies) and formhistory.sqlite (saved form data) * logins.json and key3.db for the passwords. * permissions.sqlite and possibly content-prefs.sqlite for the permissions and Site Preferences * cert8.db for stored intermediate certificates * sessionstore.js for (pinned) tabs