This site is being deprecated.
Please see the official X‑Plane Support page for help.
You can run the X-Plane installer/updater in update mode and it will replace any broken or altered files in your installation. If that doesn't fix it, I'd say temporarily remove all your third-party add-ons, then gradually add them back in until you find the one that's causing the problem.
Unless there is a bug in the installer (unlikely!), a clean reinstall is unnecessary; it will be no different than running the updater and removing your add-ons. (It's a lot faster that way, too!)
This site is no longer being actively maintained.