If you are installing SQL Server on Windows 8 or higher version of Windows, Microsoft .NET Framework 3.5 might not be installed by default. In order to ensure successful installation of all SQL Server features that require Microsoft .NET Framework 3.5, confirm that Microsoft .NET Framework 3.5 is installed or enabled prior to running SQL Server setup. If Microsoft .NET Framework 3.5 is not installed or enabled prior to SQL Server setup, Windows will attempt to install Microsoft .NET Framework 3.5 during the SQL Server installation process. An incomplete installation of SQL Server may result if Windows is not able to successfully access and install Microsoft .NET Framework 3.5.