Plex Media Server needs to be able to run on Windows in kiosk mode / without explorer OR Windows Server Core natively. Having the logs filled with WARN - Shell_NotifyIcon(NIM_ADD) failed: 0x0 every 5 seconds is not cool.
It is not a dependence on explorer. Plex server simply tries to communicate with its ‘tray icon’ app, which doesn’t run in Kiosk mode.
Simply add the parameter -noninteractive to the command line which invokes Plex Server.
Why Kiosk mode?
I think a plex client app like the UWP app from Windows app store is more suited in such a situation.
Try running Plex server as a Windows system service instead. That way it is started as soon as the machine is booted up, no matter if someone is logged in and whether it is in Kiosk mode or as a normal user.
Early 2021 clean-up: implemented/explained
