I installed the HPLIP GUI on Linux Mint 18.0 Cinnamon. Everything is working fine but the system tray icon. It does not appear
in the system tray. As from this post: http://linuxforums.org.uk/index.php?topic=10323.0
I understood that it seems like
hp-systray is attempting to start before the system tray is loaded.
As for cinnamon on Mint 18.0 it is no longer needed to change the command from hp-systray
to "sh -c sleep 15; exec hp-systray"
Menu-->Preferences->Startup Applications. It is possible to specify a delay time now. I specified a delay time of 15 seconds and the HPLIP system
tray icon now appears in the system tray.
If anyone had the same problem with HPLIP in Linux Mint 18 Cinnamon, here's the solution.
Thanks to Mark Greaves for the solution given in the post http://linuxforums.org.uk/index.php?topic=10323.0