Step: 1. Command Line :

-- Insert the Windows Sever 2012 installation media.
-- Open Command Prompt as Administrator.
-- Execute the following command:

C:\Windows\system32> dism /Online /Enable-Feature /FeatureName:NetFX3 /All /Source:D:\Sources\SxS\ /LimitAccess

Step: 2. GUI Mode :

-- Insert the Windows Sever 2012 installation media.
-- Open Server Manager.
-- On the Add Roles and Features wizard, click on "Specify an alternate source path".
-- Enter D:\Sources\SxS\ to point to the Server 2012.
-- Click OK.


Note: Once done installing through the GUI or command prompt, if you navigate back to the Add Roles and Features Wizard, you should see the feature has been successfully installed now.

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