Problem

When you try to install .NET Framework 3.5 on machines with Microsoft Windows Server 2012 or Windows 8 you may receive the following error:

Cause

When you start installing .NET Framework 3.5 from Add features, Windows will tries to connect to Windows Update to download the required information for .NET Framework. And if your machine/server had no internet connection or unable to connect with Windows update service, this issue may occur.

According to Microsoft support, in Windows 8 and Windows Server 2012 .NET Framework is a Feature on Demand, the binaries and other files associated with the feature are not included.

Solution

Steps for Windows 8

1. Insert the Windows 8 installation media
   
2. Open Command Prompt as an administrator, run the following command:
   

Dism /online /enable-feature /featurename:NetFx3 /All /Source:D:sourcessxs /LimitAccess

Where D: is drive letter for the DVD drive or for the Windows 8 installation.

Steps for Windows 2012

1. Insert the Windows Server 2012 installation media.
   
2. Use Windows PowerShell and run the following command:
   

Install-WindowsFeature –name NET-Framework-Core –source D:sourcessxs

Where D: is drive letter for the DVD drive or for the Windows 8 installation.

Abduljalil Abolzahab