Did you reset Firefox and create a new profile? When you reset Firefox then a new profile is created and some personal data (bookmarks, history, cookies, passwords, form data) is automatically imported and the current profile folder will be moved to the desktop to an "Old Firefox Data" folder. 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 profile, but be cautious not to copy corrupted files to avoid carrying over problems. You would have to copy the signons.sqlite and key3.db files from the "Old Firefox Data" folder to the current Firefox profile folder. Note that Firefox 32 and later will use logins.json instead of signons.sqlite. *https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox If you use the Time Machine then you can also try to recover files via that application. *http://www.apple.com/support/timemachine/