.NET 2, 3.5 and 4+ are distinct and updated differently. Vista shipped with .NET 3.0 and automatically updated to .NET 3.5. .NET 4.x is not an automatic updat

.NET 2, 3.5 and 4+ are distinct and updated differently. Vista shipped with .NET 3.0 and automatically updated to .NET 3.5. .NET 4.x is not an automatic update on Windows Vista, it has to be manually selected and added with admin rights .NET 2 and 3.5 are disabled by default on Windows 8/8.1/10 and require admin rights to enable them. So, there's no version of .NET in and of itself that will work on Windows Vista, 7, 8, 8.1 and 10. The one exception is if you specifically build a .NET 2 or 3 app and list compatibility with .NET 3/4.5 in the packaging manifest, then it will work with all the bundled versions of .NET on Windows Vista and later releases.