Delete the localstore.rdf file in the profile folder.

1. Go to Firefox button/Help => Troubleshooting Information => Open Folder/Directory
2. A new file manager window should now show, close firefox.
3. Delete the localstore.rdf or localstore file.
4. Open firefox and test it.

for more info refer to: http://kb.mozillazine.org/Corrupt_localstore.rdf

Do you still have the Navigation Toolbar visible?

Make sure that toolbars like the "Navigation Toolbar" and the "Bookmarks Toolbar" are visible.

• Firefox menu button > Options
• View > Toolbars (press F10 to display the menu bar)
• Right-click empty toolbar area

Use Toolbar Layout (Customize) to open the Customize window and set which toolbar items to display.

• if missing items are in the toolbar palette then drag them back from the Customize window on the toolbar
• if you do not see an item on a toolbar and in the toolbar palette then click the "Restore Default Set" button to restore the default toolbar setup

• https://support.mozilla.org/kb/How+to+customize+the+toolbar
• https://support.mozilla.org/kb/Back+and+forward+or+other+toolbar+items+are+missing