Where are you trying to download X-Plane too?
The recommended location is the desktop and not your normal operating system drive. This is normally the "C" drive. X-Plane is a dedicated standalone file system but as others have stated in this forum it can still become corrupted if you do download to that location.
An alternative, if you have the ability to do so, is to download to a dedicated drive just for X-Plane, with nothing else on that drive.
Hope this may help as well.