I'm in the process of updating some applications from use of Boost 1.28.0 to 1.29.0, using MSVC7. I've noticed that a number of static assertions that used to compile now generate errors. The assertions all use is_integral to perform a type validation - e.g.: BOOST_STATIC_ASSERT(::boost::is_integral::value); This produces an error of the form: c:\Perforce\Development\Web\cppinclude\domestic\Application Framework\State Machine Engine\StringSerializer.h(145) : error C2027: use of undefined type 'boost::STATIC_ASSERTION_FAILURE<x>' with [ x=false ] c:\Perforce\Development\Web\cppinclude\domestic\Application Framework\State Machine Engine\StringSerializer.h(143) : see reference to class template instantiation 'sme::StringSerializer<_StringType,>::StringWriter<<template parameter>>' being compiled c:\Perforce\Development\Web\cppinclude\domestic\Application Framework\State Machine Engine\StringSerializer.h(169) : see reference to class template instantiation 'sme::StringSerializer<_StringType,>' being compiled I believe that the data type is integral, and is complete at compile time. Any known reason why this would happen? Randy Bowen