Hi, After updating a project to use Boost 1.59 from 1.57 I am getting link errors like this: Undefined symbols for architecture i386: "boost::log::v2_mt_posix::basic_formatter<char> boost::log::v2_mt_posix::parse_formatter<char>(char const*, char const*)", referenced from: boost::log::v2_mt_posix::basic_formatter<char> boost::log::v2_mt_posix::parse_formatter<char>(char const*) BOOST_LOG_DYN_LINK has been defined and the build works with 1.57. This is on OSX 10.10.5 with Xcode 6.4 and with command line builds using clang (Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)). Boost was built using this command line: ./b2 --prefix=$HOME/rp/boost-1_59_0 cxxflags="-stdlib=libc++ -arch i386 -mmacosx-version-min=10.7" linkflags="-stdlib=libc++ -arch i386 -mmacosx-version-min=10.7" --with-python --with-signals --with-thread --with-date_time --with-filesystem --with-regex --with-chrono --with-log link=shared architecture=x86 install What do I need to do fix this? Glenn