Windows 7 Security Issues When Opening MSTS Files

Route_Riter Help file won't open - "Navigation to the web page was canceled"

One of Microsoft's security updates included changes to the InfoTech protocol that blocks the ability to view remote content. These changes were introduced to reduce security vulnerabilities in HTML Help.

The net effect of this "security update" is that you may find you are unable to open the Route Riter Help file: you may see a message such as this:

Clicking on any option in Contents doesn't improve things at all

Fortunately, the cure is simple: browse to "route_riter.chm" in Explorer, Right-click, select "Properties", and click on "Unblock".

You will now be able to view the help file.

Windows Cannot Open this File

Another effect of Microsoft's security updates that randomly blocks the ability to view/run downloaded content.

Right-click on the EXE file, select Properties:

At the bottom of the "General" tab, click "Unblock", then "ok".

You can check that W7 has unblocked the file by repeating the above procedure.
The Security area will be blank.

Windows will now run the installer as requested.