This warning occurs when (under certain circumstances) the Intel compiler is forced to call the Microsoft
compiler and the Microsoft compiler can't compile the code.  One of these cases is when you
use the /FD (generate file dependencies) switch. In order to generate the file
dependencies the icl driver must call cl.

Normally the Microsoft compilation works fine and the user can't even tell that happened.
But under certain circumstances there might be something in the source file which the
Microsoft compiler can't handle. One example would be a C99 extension like _Complex types.

So you would see this warning for example if you tried to use the C99 extension that the Intel compiler supports
under the /Qstd=c99 (but the Microsoft compiler does not)  and also put /Fd on the command line,
i.e.:

!% cat t.c

int main() {
  float _Complex c;
  return 0;
}
!% icl /Qstd=c99 -c /FD t.c
Intel(R) C++ Compiler for applications running on IA-32, Version Mainline  Beta
 Build x
Built May 21 2009 12:47:08 by jward4 on SPTXPW2012 in F:/cmplr/dev_cfe/dev
Copyright (C) 1985-2009 Intel Corporation.  All rights reserved.

t.c
icl: warning #10210: problem with Microsoft compilation of 't.c'
!%

You can determine what is in your code that the Microsoft compiler can't handle by just compiling with cl
instead of icl.

Judy