You can copy the cookies.sqlite file from the "Old Firefox Data" folder on the desktop to the current profile folder. You can use this button to go to the current Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox ----- You can copy files like these to the current Firefox profile folder to recover specific data. * bookmarks and history: places.sqlite * bookmark backups: JSON backups in the bookmarkbackups folder * SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data) * logins.json and key3.db (decryption key) for Passwords saved in the Password Manager * cert8.db for stored intermediate certificates (Certificate Manager) * persdict.dat for words you added to the spelling checker dictionary * permissions.sqlite and possibly content-prefs.sqlite for Permissions and Site Preferences * sessionstore.js for open tabs and pinned tabs and tab groups