As part of installing CRM 2013 for one of our clients we have faced an issue where we couldn’t enable .Net Framework 3.5 in windows server 2012 R2. Here is why and what did we do to fix it.

possible reasons:

  1. Windows Server R2 Update might have the security update 2966827 or 2966828 already installed in the server and this would block enabling .Net Framework 3.5.
  2. Internet connection in server is not working

In case of reason#1 – you may uninstall security update  2966827 or 2966828 and try to enable .Net 3.5


In case of reason#2 – you can select the alternate source path which has the windows server R2 source files to install .Net Framework 3.5

Steps to follow:

Step 1. Select  ‘ Specify alternate source path’ while adding .Net 3.5 feature

Add Roles And Features-Net3_5

Step #2: provide path to the source folder [usually <Image drive>:SourcesSxS ] and continue with the feature enabling. This should work.

Add Roles And Features-Net3_5_2