I downloaded Windows 8.1/Explorer 11 preview. Norton 360 no longer functioned so I ended up installing 360 beta 22.
Good news. Works with Firefox. Bad news - not with Explorer 11.
The toolbar drown-down menu shows "Norton toolbar," but it is not selectable.
For what it's worth.... I would recommend holding off on the "preview".... Its ended up being a PIA
Regards and thank you.
Mike