The problem happened likely because two math libraries were linked into the application. With adding the _IPP_PARALLEL_STATIC, the libmmt.lib library was implicitly included into linking line. While the static link to CRT (/MTd) in Visual Studio 2010 will also add the VS runtime libraries. The _log function are defined in both libraries, and report such error. It is right that you can use /nodefaultlib option to remove the problem.