This article from InSource shows how to remove 2 security updates which block the feature of .NET 3.5.1 from being enabled on Server 2012 R2.
- Author: Lewis Talley
- Published: 8/16/2016
- Applies to: MSSQL 2014
If you encounter this error when attempting to enable .NET 3.5.1 (which is a requirement for installing MSSQL 2014):
There is a fix from Microsoft to manually remove 2 security updates..
or more simply you can run this update which will remove them for you.