Try redownloading the installer here:
Otherwise, make sure it isn't being blocked by the firewall.
If neither of those solve the problem, run the installer once again and wait for it to crash (you'll see why in a second). Then, go into Windows Event Viewer so Windows can communicate with us what happened:
1.) Go to the Start menu, click Control Panel, then System Maintenance, then Administrative Tools, then double-click on "Event Viewer".
> Otherwise, you can go to the Start menu search and type "eventvwr.msc", then press enter, allowing administrative access if prompted.
2.) Under "Event Viewer (Local)", expand "Windows Logs". There, you can take a look through the "Application" and the "System" sections, where the recent errors/crashes/notices should already be visible. Expand the one relevant to the X-Plane 11 Installer and Copy & Paste what it says. Thanks.