Some of our users have reported that xmr-stak linked from our official website fails to run with error message saying msvcr120.dll can’t be found. This file is part of Microsoft Visual C++ 2013 run-time. As our builds are compiled using Visual C++ 2017 (15.9), we have not bundled installer of the older run-time libraries.
There is known issue with some of the builds of Visual Studio C++ 2013 run-time installers that cause the files getting deleted if both 32-bit and 64-bit versions are installed. For more information, please read the official Knowledge Base article (KB3138367).