When trying to launch the SharePoint 2016 Beta 2 Products Preparation Tool (Prerequisites Installer) on Windows Server 2012 R2 the following error occured:

The program can’t start because api-ms-win-crt-heap-l1-1-0.dll is missing from your computer. Try reinstalling the program to fix this problem.

The solution is to download and install Visual C++ Redistributable for Windows (64-bit).