Hi John, I have an up to date copy of boost trunk on a new machine (u233) running RHEL 6.0 kernel (Santiago). You can see the results on the trunk page under Ornl-intel-11.1.064. For some reason the configure script is having trouble locating the boost main tree. I tried adding --with-boost=... to no avail. Is this a recent problem or perhaps this is the first attempt under 6.0? Any ideas? -- Noel [bkn@u233 config]$ ./configure *** ./configure: boost configuration utility *** Please stand by while exploring compiler capabilities... Be patient - this could take some time... Note that this test script only gives an approximate configuration - you will need to test the results carefully using the boost regression test suite before using the results. *** Info : .cpp used as extension for tests checking for boost main tree... not found configure: error: The boost main tree was not found. Specify its location by the --with-boost option.