Check the box for (this includes 2.0 and 3.0).
On the final page, click the link "Specify an alternate source path" .
Open and click Manage > Add Roles and Features . Click through the wizard until you reach the Features page.
This is often more reliable and faster for automated deployments or when the GUI wizard fails. Installing .Net 3.5 on Windows 2012 R2 - Server Fault
Installing the on Windows Server 2012 R2 requires a different approach than typical software. There is no standalone "2.0-only" installer for this OS; instead, it is bundled as part of the .NET Framework 3.5 feature. Primary Offline Installation Methods
Because many servers lack direct internet access, you must use local installation media (the ISO or DVD used to install the OS) as your source. Method 1: Using Server Manager (GUI)