Hi! I am experiencing quite odd errors with the serialization library: My program compiles fine, but crashes when static constants are declared, i.e. before the program even starts with main(). The debugger tells me that some singleton declared in the seralization library conflicts: Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000 0x0000000100003aaf in H5::DataType::DataType () at singleton.hpp:149 149 BOOST_DLLEXPORT T & singleton<T>::instance = singleton<T>::get_instance(); Any suggestions would be great here. What makes it even harder to understand is the fact that the exact same code runs perferctly on a Linux machine, whereas the crash is on MacOS 10.6. My setup here is a boost 1.43.0 compiled with gcc 4.5 from pacports (or apples gcc 4.2, no difference). It seems that the singleton does things which are not allowed on a 10.6 MacOS machine... Many thanks for help, Sebastian Weber