Hi, When I create a "Windows Forms Application" under Visual C++ Express and add these lines to the main .cpp file: #include <boost/program_options.hpp> static boost::program_options::variables_map vm; and then set the the project property 'Common Language Runtime support' to /clr (/clr:pure make compilation fails), I got an assertion failure on dbgheap.c line 1414, expression: _CrtIsValidHeapPointer(pUserData) on the line: BOOST_PROGRAM_OPTIONS_DECL std::string arg("arg"); in value_semantic.cpp. Compiler command line: /Od /I "G:\Program Files\boost-cvs\boost" /D "WIN32" /D "_DEBUG" /D "_UNICODE" /D "UNICODE" /FD /EHa /MDd /Yu"stdafx.h" /Fp"Debug\po_assert.pch" /Fo"Debug\\" /Fd"Debug\vc80.pdb" /W3 /nologo /c /Zi /clr /TP /errorReport:prompt /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Windows.Forms.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.XML.dll" Linker command line: /OUT:"G:\Projects\po_assert\Debug\po_assert.exe" /INCREMENTAL /NOLOGO /LIBPATH:"G:\Program Files\boost-cvs\boost\stage\lib" /MANIFEST /MANIFESTFILE:"Debug\po_assert.exe.intermediate.manifest" /DEBUG /ASSEMBLYDEBUG /PDB:"g:\projects\po_assert\debug\po_assert.pdb" /SUBSYSTEM:WINDOWS /ENTRY:"main" /MACHINE:X86 /FIXED:No /ERRORREPORT:PROMPT Using a pointer and dynamically allocation a variables_map ends the same way... What am I doing wrong ? Or is it a known problem ? Thank you. JD