Returns a Task that will be completed with success when existing messages of the target actor have been processed and the actor has been terminated. Useful when you need to wait for termination or compose ordered termination of several actors, which should only be done outside of the ActorSystem as blocking inside ActorBase is discouraged. IMPORTANT: the actor being terminated and its supervisor being informed of the availability of the deceased actor's name are two distinct operations, which do not obey any reliable ordering. If the target actor isn't terminated within the timeout the Task is completed with failure. If you want to invoke specialized stopping logic on your target actor instead of PoisonPill, you can pass your stop command as a parameter: GracefulStop(someChild, timeout, MyStopGracefullyMessage).ContinueWith(r => { // Do something after someChild starts being stopped. });