First, do not use TerminateThread() to forcely terminate thread. The best way is let the thread terminate itself. If you want to terminate thread while thread is running, set a flag to notify the thread and let it self-terminate. Read the book "Multithreading Applications in Win32", a good book you need to read before you use multithread. Second, you need to check your code to see where you dynamic created variable but not delete it upon thread exit. You need to check this yourself, no other people can help you.