I haven't tracked down what include order is causing this, but I'm getting: c:\dev\opt\include\boost/utility_fwd.hpp(21) : fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'msc1.cpp', line 1794) Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information Of course MSVC doesn't have header include tracing. I've been working around it with spurious includes of . Any ideas? Thanks, Tom ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------