This site is being deprecated.
Please see the official X‑Plane Support page for help.
What version of the installer are you using? You can find it by right clicking and picking "properties" on Windows or "Get Info" on Mac. If you are using anything except version 3.40r3, please go to the downloads page on our site and download the installer again. I just heard we may have had old versions available by mistake but the site should be updated now.
It would be helpful to see a copy of the X-Plane installer log.txt file that should be on your desktop. Some basic troubleshooting things are:
This site is no longer being actively maintained.