Installing .NET Framework 3.5 on Windows Server 2012

Installation of .NET Framework on Windows Server 2012 fails with below error when we try to install it from server manager using default options.

Basically it complains that installer could not find source file.

On the other hand, we can no longer directly install .NET Framework 3.5 by directly downloading it and then executing the setup.

So please follow below steps to install / enable Framework 3.5 on Windows Server 2012

Step 1:
Have Windows Server 2012 Installer Image on your server where you are installing or have it accessible. Basically we need to have Windows Server 2012 Installer available as source. For this example, I mounted it as F$.

Step 2:

Open Server Manager and Select Add Roles and Features. Then please follow subsequent screenshots.

Note: No need to select any role here as .NET Framework 3.5 is a feature. Then proceed to Next page.

Select .NET Framework 3.5 Feature. Here I am selecting default installations only. You may want to add more components as needed.

Here you can see that Installer is warning about “non-availability” of source path. So please select option of Specify an alternate source path and mention where your windows installer media is available. (Per Step#1). For me, it is F:\sources\sxs. Please refer to screenshot below for next steps.

Now click OK and it will close this page.

Click Install now. It will work using the correct source path you mentioned.

Installation is successful now. There is no need to restart Server and you will be able to start using this Feature immediately.

Note:

This may be a bug and should be fixed in a future service pack release. However I experienced that we need to do this installation manually otherwise other installations which depends on .NET Framework 3.5 (like SQL Server 2012 or 2008//R2) will fail. 

This is tested on Windows Server 2012 Datacenter Edition (Version 6.2 Build 9200)