Adding .Net Framework 3.5 feature failed.
When trying to install .Netframework 3.5 you receive an error that the feature installation has failed.
This problem occurs because security updates 2966827 and 2966828 for Microsoft Security Bulletin MS14-046 for the .NET Framework 3.5 require metadata that is added to the system only if the Microsoft .NET Framework 3.5 feature is enabled on the system.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the “Applies to” section. The issue is now resolved by update 3005628. The workaround that is provided in the next section still unblocks customers, depending on their situation.
Alternately the feature can be installed using DISM which can be executed using CMD and run as Administrator. This option can be used to do an Offline installed of .NetFramewortk using the Windows installation media.
To get started you need to insert a Windows Installation Media and execute the following.
Dism /online /enable-feature /featurename:NetFx3 /All /Source:Z:\sources\sxs /LimitAccess
and that is how you can quickly install .NetFramework 3.5.