The .NET Framework 4.5 is included with Windows 8 and installed on your computer with the operating system. However, the .NET Framework 3.5 is not automatically installed with Windows 8. To run applications that require the .NET Framework 3.5 on Windows 8, you must enable version 3.5 on your computer. There are two ways you can do this: by installing or running an application that requires the .NET Framework 3.5 (that is, by installing the .NET Framework 3.5 on demand), or by enabling the .NET Framework 3.5 in Control Panel. Both options require an Internet connection.
Important notes:
- Use the .NET Framework 3.5 for applications built for versions 2.0 and 3.0 as well as 3.5.
- Installing a Windows language pack on Windows 8 before installing the .NET Framework 3.5 will cause the .NET Framework 3.5 installation to fail. Install the .NET Framework 3.5 before installing any Windows language packs.
- Windows CardSpace is not available with the .NET Framework 3.5 on Windows 8.