I've managed to get my signals access violation to happen in a relatively simple test program on win64. I'm attaching my example source code to this email. If anyone needs anything else to reproduce the problem, please let me know. This program works when statically linked, but not when dynamically linked, so if someone can spot a bad compiler/linker flag, that would help too. I built boost with: bjam --toolset=intel address-model=64 link=shared runtime-link=shared --with-signals stage Also, I had to edit intel-win.jam to change icc.exe to icl.exe so that the compiler would run properly. I built my test application with: icl /EHsc /MD /I. test.cpp /link /subsystem:console /LIBPATH:stage\lib /NODEFAULTLIB /ENTRY:mainCRTStartup /FORCE:multiple boost_signals-iw-mt-1_34.lib msvcprt.lib msvcrt.lib libirc.lib libmmd.lib If you build with static linkage (obviously, rebuild boost without the shared link settings), the executable works fine (with libboost_signals-iw-mt-1_34.lib). -- Nick