Windows 2012, Windows 2012R2 and Windows 2016 each have version-specific install media for .Net 3.5. If you install x86 version of Win8, Win8.1 or Win10 there is also separate media for these. If you use the wrong version of the install media then .Net3.5 will not install correctly.
The following command should get .Net3.5 installed:
DISM.exe /online /enable-feature /featurename:"NetFX3" /All /Source:"your sxs media" /LimitAccess
If you are installing on Server Core then you must install the following components:
NetFx2-ServerCore;NetFx3-ServerCore;ServerCore-WOW64;NetFx2-ServerCore-WOW64;NetFx3-ServerCore-WOW64
The 'your sxs media' folder will be the \sources\sxs folder from your Windows install media. It can be copied top a disk location if you want or referenced direct from the DVD.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
When I give food to the poor they call me a saint. When I ask why they are poor they call me a communist - Archbishop Hélder Câmara