Comment 27 for bug 1532226

Anyone affected, could you please try to replace your ~/.config/upstart/unity-panel-service.conf with:
  http://pastebin.ubuntu.com/15670770/

If that works, please also replace the "start on started unity7" with "start on starting untiy7" (i.e. http://pastebin.ubuntu.com/15670852/) and let me know...