Tools and methods are described herein for discovering race condition errors in a software program. The errors are discovered by deliberately causing a processor executing the test program to switch threads at intervals other than normally scheduled by an operating system. The thread switching is caused upon occurrence of selected events. The intervals may be selected automatically or with user input. Furthermore, thread switching may be caused during conditions more likely to cause race condition errors. For example, thread switches may be caused between threads that share control of a memory device or while the processor is executing instructions related to synchronization tools (e.g. locks, mutex, etc.).