The bug did not go away for me either, but I noticed that in the Startup menu, the command line is this:
sh -c "sleep 15; exec hp-systray"
I changed 15 to 45, and ever since no error message at startup. I am just a regular user, so just gave it a try, but maybe somebody knows, whether it is an option that delays startup somewhat, and this way Hplip does not want to climb onto the system tray "too early".
The bug did not go away for me either, but I noticed that in the Startup menu, the command line is this:
sh -c "sleep 15; exec hp-systray"
I changed 15 to 45, and ever since no error message at startup. I am just a regular user, so just gave it a try, but maybe somebody knows, whether it is an option that delays startup somewhat, and this way Hplip does not want to climb onto the system tray "too early".