In release mode (debug to libboost_unit_test_framework-vc80-mt-sgd-1_34.lib is OK, and dll debug and release libs also OK) Compiling... test_tools_test.cpp Linking... libboost_unit_test_framework-vc80-mt-s-1_34.lib(exception_safety.obj) : error LNK2005: "void * __cdecl operator new[](unsigned int)" (??_U@YAPAXI@Z) already defined in libcpmt.lib(newaop.obj) I:\boost-06-01-13-0500\libs\test\build\msvc71_proj\Release\test_tools_test_s tatic.exe : fatal error LNK1169: one or more multiply defined symbols found Suggestions about what I am doing wrong? Thanks Paul PS Trying to avoid transition to monitor defenestration mode ;-) -- Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB Phone and SMS text +44 1539 561830, Mobile and SMS text +44 7714 330204 mailto: pbristow@hetp.u-net.com http://www.hetp.u-net.com/index.html http://www.hetp.u-net.com/Paul%20A%20Bristow%20info.html