I also have this problem. Every time at startup the "No system tray detected" erro message shows up. I use Ubuntu 17.10 and HPLIP 3.17.11 (last version at the time of writing).
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1714659 Title: HPLIP is not compatible with modern GNOME (No system tray detected on this system. Unable to start, exiting.) To manage notifications about this bug go to: https://bugs.launchpad.net/hplip/+bug/1714659/+subscriptions -- ubuntu-bugs mailing list email@example.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs