This site is being deprecated.
Please see the official X‑Plane Support page for help.
I am not from Laminar Research; just a flight simmer from downunder.
Without deleting X-Plane in total run the installer file again. In doing so it should look for and install any files that are missing and or replace any files that are corrupted in any way. If it finds a corrupted file it may ask if you want to replace the file. Generally answer yes but you may need to consider each file when asked.
Hope this works for you.
This site is no longer being actively maintained.