Network Manager Icon disappeared 14.04
I was able to fix it by changing nm-applet to launch with dbus-launch nm-applet. To see if this will work for you, try running dbus-launch nm-applet and see if that shows up properly. To make the fix permanent, I edited /etc/xdg/autostart/nm-applet.desktop and changed
Exec=nm-applet
to
Exec=dbus-launch nm-applet
This fixed it for me
sudo apt-get install indicator-applet-complete