First, I would always close everything down, then open Windows, then open Firefox. If is the whole Navigation Bar that is missing - right click on toolbar space and check Navigation Bar. If it is just the Address Bar (this will undo any special customization you've done) Courtesy of '''TonyE''' - To restore it, try the option to "Restore the default toolbar set" as shown here - https://support.mozilla.com/kb/Back+and+forward+or+other+toolbar+items+are+missing If that does not work, try the option to "Reset toolbars and controls" in the same article.