Consider the following problem.  You are building out a new SharePoint 2013 web front end (WFE) onto Windows Server 2012.  As part of that build process, you need to install all the usual features, one of them being .NET 3.5 framework.  You launch the Add Roles and Features Wizard, and work your way through setting the appropriate roles and features needed in order to enable the server to host SharePoint 2013.  When you come to the .NET 3.5 Framework feature, you experience a problem.  Despite many efforts, you find that the .NET 3.5 Framework feature can not be added to a new Windows Server 2012 build.  Each time you attempt to install the feature, you experience the following error (when using the GUI - A similar message is displayed in the PowerShell, when installing via script):

No matter how the source disk is made available to the Add Feature wizard, whether using different network drives, mounting it locally, copying it to the local drive, etc., the error message is the same. A similar message is encountered when attempting to add the .NET 3.5 feature via PowerShell script.  This is the first time you have encountered such an error building a new Windows Server 2012 instance for SharePoint 2013. You last successfully created a new Windows Server 2012 instance in July 2014.


  1. Uninstall KB2966827.
  2. Reboot.
  3. Add the .NET 3.5 Framework feature and all its subfeatures.
  4. Reboot
  5. Re-install KB2966827.



  • Many thanks to Steve at AskVG and to to my team's lead sysadmin for originally presenting and finding the solution to this vexing problem.
  • Steve indicates that three updates are the cause of this problem: All of these updates are associated with the MS14-046 security update of August 12, 2014.  Only KB2966827 applies to Windows Server 2012.