What is the difference between ManualResetEvent and AutoResetEvent in .NET?

Yes. It's like the difference between a tollbooth and a door. The ManualResetEvent is the door, which needs to be closed (reset) manually. The AutoResetEvent is a tollbooth, allowing one car to go by and automatically closing before the next one can get through.

Just imagine that the AutoResetEvent executes WaitOne() and Reset() as a single atomic operation.

The AutoResetEvent also guarantees to only release one waiting thread.