Installing Microsoft .Net3.5 on Windows Server 2012 R2

Looking at the title it looks damn simple but I had to spend quite a lot of time to get this done. Windows server 2012 will not allow to install .NET Framework 3.5 by triggering the 'exe' or the installer file. A message is returned that Windows server roles and features cannot be automatically installed or uninstalled via Windows Features control panel. It will prompt you to go to the 'Server Manager' or to use the 'Server Manager cmdlets' for Windows PowerShell.


However when I tried to use the recommended method following error was returned and the installation of .NET Framework 3.5 failed. Error screen looks like this:  

Windows logs present in 'C:\Windows\Logs\CBS' will have error messages and code '0x800F0906'.


Generally people try to retrofit sources available on Internet by putting them in source path or specifying new source path. It did not work for us. What worked for us was the following:

Steps to Resolve:

 


Click the search icon on desktop as shown in the image below:

Type 'Group Policy' in the search text box

Open the 'Edit Group Policy' returned in the search item


Navigate to Administrative Templates-->System 


Scroll down in 'System' pane and open 'Specify settings for optional component installation and component repair'

Select the Enabled option. By default it will be 'Not Configured'


Make sure check the checkbox for 'Contact Windows Update directly to download repair content instead of Windows Server Repair Services (WSUS)' 

Click on 'Apply' and 'Ok'


Retry the installation while you are online.