If you get this with WIN32_LEAN_AND_MEAN, and you are not using OLE:
commdlg.h(572): error #2001: Syntax error; found 'LPUNKNOWN' expecting '}'.
put this before commdlg.h and enjoy fast compiling again.
#ifndef LPUNKNOWN
typedef void* LPUNKNOWN;
#endif
#include <commdlg.h>