You need the multibyte DLLs in order to build an MFC project in Visual Studio 2015 that has the Character Set property set to Use Multi-Byte Character Set or Not Set.

Visual Studio 2013: Download the DLL at Multibyte MFC Library for Visual Studio 2013.

Visual Studio 2015: The DLL is included in the Visual C++ setup components. Visual C++ and MFC are optional install configurations in Visual Studio setup. To make sure that MFC is installed, choose Custom in setup, and under Programming Languages, make sure that Visual C++ and Microsoft Foundation Classes for C++ are selected. If you have already installed Visual Studio, you will be prompted to install Visual C++ and/or MFC when you attempt to create an MFC project.

Visual Studio 2017: The DLL is installed with the Desktop Development with C++ workload when you select MFC and ATL support from the Optional Components pane.

See Also

MFC Library Versions