ubuntu 14.04 gnome "No system tray detected on this system" where is start up program
This appears to be a problem with older systems. A workaround is to modify the startup desktop connection file (/etc/xdg/autostart/hplip-systray.desktop) from
Exec=hp-systray -x
to
Exec=sh -c "sleep 15; exec hp-systray -x"
/etc/xdg/autostart/hplip-systray.desktop
$ gnome-session-properties