If you are using Visual Studio C++ 2020 Express Edition rather than the full SDK, you need to do the following steps to set up your build environment for building Intel64 applications (just using the usual command prompt shortcut in the All Programs menu will NOT work). I discovered this working with Intel recently and Steve Lionel via Premier Support and felt it important to share since it does not seem to be documented anywhere else.
call "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /Release /x64
set CL=
set ROOT=%IFORT_COMPILER12%
set TARGET_ARCH=INTEL64
SET ARCH_PATH=INTEL64
set ARCH_PATH_MPI=EM64T
SET PATH=%ROOT%\bin\%TARGET_ARCH%;%ROOT%\redist\%ARCH_PATH%\compiler;%PATH%
SET PATH=%PATH%;%ROOT%\redist\%ARCH_PATH%\mpirt;
set LIB=%ROOT%\compiler\lib;%ROOT%\compiler\lib\%ARCH_PATH%;%LIB%
set INCLUDE=%ROOT%\compiler\include;%ROOT%\compiler\include\%ARCH_PATH%;%INCLUDE%
if defined I_MPI_ROOT set IMPI_BIN=%I_MPI_ROOT%\%ARCH_PATH_MPI%\bin;
set PATH=%IMPI_BIN%%PATH%
color
call "C:\Program Files (x86)\Intel\Composer XE 2011 SP1\mkl\bin\mklvars.bat" intel64 vs2010
