This impacts Windows users only:

Please install Microsoft Visual C++ Redistributable for Visual Studio 2017 and Visual C++ Redistributable Packages for Visual Studio 2015 Update 3 from this page:

Check to see if any .NET frameworks is installed:
Easiest way to find out is to go to Control Panel, open "Programs and Features" then scroll down.
If you don't have anything starting with "Microsoft .NET" please go to https://www.microsoft.com/net/download/framework and download .NET Framework 4.6.1

Note:
    The latest version of Internet Explorer needs to be installed.
    It is highly recommended that RGT is installed in C:\Road Grand Tours to avoid any file permission error (if installed in any other folder run RGT by right click and selecting "Run as administrator" to avoid any errors)