Yes, after the reinstallation you can restore aircrafts, sceneries and plugins, the worst scenario is that you've to re-activate your payware products but I do not see problems about it.
You'll backup the demo version if you'll backup the whole installation, just do a copy of those three folders (well, maybe its better to backup the whole Resources folder, not only Resources/plugins, so you'll backup even your preferences) unless you changed even some system files (let's say, cloud and/or runways textures).
But that updater work only with the dvd version, that's the reason the sim now ask you for a product key (given only with the digital version sold by Laminar, different than the one sold by Steam) or the dvd1.
You shouldn't have lost your add-ons: do a backup of the Aircraft, Scenery Custom and Resources/plugins folders just to be sure, then if I'm not wrong and I recall correctly Steam should give you the chance to check your product and fix it if needed, there'd be an option by clicking somewhere with the right mouse button (sorry I can't be more precise as I don't use it).
Hello Jeff,
I wasn't aware about a 'demo mode' of the Steam version, which X-Plane updater are you talking about?
If you used the installer available on the x-plane.com site I strongly believe there's no other way than re-download the full installation from Steam, but of course I could be wrong.
To setup a joystick button associated with ixeg reference / 733 / autopilot / LNAV_mode_toggle , I could not find in X -Plane that recognizes it.
Please , how should I proceed?