I noticed that if I use boost::thread_specific_ptr (thread local storage) and terminate my console application (on windows) with Ctrl+Break, I always get a message box and assertion error from the boost thread library: Assertion failed: attached_thread_count == 0, file .......\msvc71\libs\thread\build\..\src\tss_hooks.cpp, line 131 Is this a known problem and are there any fixes? The test case is #include <boost/thread/tss.hpp> #include <iostream> #include <windows.h> int main() { boost::thread_specific_ptr<int> tl_int; tl_int.reset(new int); std::cout << "Sleeping for 10 seconds ..." << std::endl ; ::Sleep(10000); std::cout << "Woke up" << std::endl ; } compiled with /DBOOST_THREAD_USE_DLL . If you press Ctrl+Break while it's sleeping you get that assertion. Valentin