Hi friends Using the freshly created MinGW 64bit build, creating the boost 1.40 libraries with bjam worked flawlessly. However, when including boost/thread.hpp, I receive the following error: In file included from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/basic_timed_mutex.hpp:14, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/mutex.hpp:8, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/mutex.hpp:14, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/detail/thread.hpp:11, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/thread.hpp:22, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread.hpp:13, from ../src/main/com/emc/schedule/DailyRepetitiveTaskComposite.cpp:2: C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/interlocked_read.hpp: In function 'void boost::detail::interlocked_write_release(void* volatile*, void*)': C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/interlocked_read.hpp:71: error: cast from 'void*' to 'long int' loses precision In file included from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/mutex.hpp:8, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/mutex.hpp:14, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/detail/thread.hpp:11, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread/thread.hpp:22, from C:\Program Files\C++\boost\boost_1_40_0/boost/thread.hpp:13, from ../src/main/com/emc/schedule/DailyRepetitiveTaskComposite.cpp:2: C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/basic_timed_mutex.hpp: In member function 'void* boost::detail::basic_timed_mutex::get_event()': C:\Program Files\C++\boost\boost_1_40_0/boost/thread/win32/basic_timed_mutex.hpp:152: error: cast from 'void*' to 'long int' loses precision make: *** [src/main/com/emc/schedule/DailyRepetitiveTaskComposite.o] Error 1 However, on the stated line, I can't even make out a cast. Is boost_thread win64 compatible? g++ version: g++.exe (GCC) 4.4.1 20090505 (prerelease) Copyright (C) 2009 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Thanks for any help and best regards Pascal