I don't have Windows OS but assume you do. If so where is your X-Plane installed at? Is it in the Program Files directory? If it is then you can get permission errors. If it is in any directory such as even C:\ root directory or C:\Windows it will likely cause permission problems or other problems when you try and run it. The best bet is to install it on the Desktop. So this is just a possibility of what may be wrong, without more information of where you installelled it or what OS. If it is Linux, similar applies. It should not be installed in any system folder. In the user /home or directly from the Desktop is alright. I am not certain about Mac OS, I have never used it but similar will probably apply there as well.