Martin Wille posted about this a couple of days ago (http://lists.boost.org/boost-testing/2005/05/1216.php), but I'm afraid it could have passed unnoticed. Some tests from Boost.(Assign|Range|PointerContainer) have the following layout #include<...> using namespace std; using namespace boost; ... #include <boost/test/unit_test.hpp> having the using directives before boost/test/unit_test.hpp is AFAICS illegal and does indeed cause problems with GCC 3.4.x and GCC 4.x, see for instance http://tinyurl.com/8payc I cannot test it, but I guess it suffices to move all the includes before any using directive. This will probably clear up dozens of tests, including some toolsets that are currently marked as unusable. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo