Prerequisites for Windows 2012 R2 Installations

To install the Application Server, Reporting, Extension servers, or ActiveX Task List on Windows® Server 2012 R2, the April 2014 update rollup for Windows® Server 2012 R2 (KB2919355) must already be applied.

CAUTION: If this update is missing, the Visual C++ 2015 Redistributable packages installed by the Workflow installer will fail. These packages must be manually uninstalled, and then the necessary Windows updates must be applied before you attempt the Workflow installation again. If you do not uninstall the Visual C++ 2015 Redistributable packages before retrying the Workflow installation, the installation will appear to be successful but the WorkflowServer service will fail to start.
Important: These recovery steps also apply if you attempt to install Workflow 2.5 SP2 on Windows® 7 Professional without SP1 or Windows® Server 2008 R2 without SP1.