I used to use a very old version of bjam and wanted to switch to the most recent version 1.77. When I use the new bjam, I encounter the following problems. o I have 2 projects with the same id, the error message is error: at nml/unit_test/Jamfile:1 error: Attempt to redeclare already registered project id '/test'. error: Original project: error: Name: Jamfile error: Module: Jamfile error: Main id: /test error: File: distmesh/unit_test/Jamfile error: Location: distmesh/unit_test error: New project: error: Module: Jamfile error: File: nml/unit_test/Jamfile error: Location: nml/unit_test After I changed the id in one project, the errors disappeared. o I do bjam again, I have this error /Users/cho//doc/boost/boost_1_73_0/tools/build/src/build/generators.jam:1127: in ensure-type from module generators error: target { PNCDF_Variable.C. } has no type Once I changed the C extension to cpp, the error disappeared. I don't have these problems using the old bjam. Are there syntax changes in the Jamfile? Please help. Thanks, Cho