I've been having a weird issue for a while with TBB. Even with the latest Windows x64 binaries (tbb40_297oss), in debug mode when I create my task_scheduler_init object by setting the number_of_threads parameter to 1, my program still runs in many threads with parallel_for. In release mode, it seems to spawn one thread, cause my Core i7 CPU is loaded on 1/8. In debug it's fully loaded and jumps across threads when debugging. And I want to debug with a single thread. Any ideas?