Which bar is missing? For example: * Top menu bar (File, Edit, View). See: [[Restore the Menu bar in Firefox]]. * Bookmarks toolbar. See: [[Bookmarks Toolbar - Display your favorite websites at the top of the Firefox window]]. * The sidebar? See: [[Use the Firefox Sidebar to access bookmarks, history, passwords and synced tabs]] -- or for the newer design -- [[Use the sidebar to access tools and vertical tabs]]. Or something else?