I can reproduce that problem consistently when I'm trying to shutdown/reboot with launched quiterss.
But now that you've mentioned mate-panel I've tried do disable tray icon in quiterss and was able to reboot without delay.
I can reproduce that problem consistently when I'm trying to shutdown/reboot with launched quiterss.
But now that you've mentioned mate-panel I've tried do disable tray icon in quiterss and was able to reboot without delay.