If a backup browser shuts down properly, it sends an announcement to the master browser that it is shutting down. The backup browser does this by sending an announcement that does not include the Browser service in the list of running services.
If a Master Browser shuts down gracefully, it will send a ForceElection datagram so that a new master browser can be chosen.
If a computer does not shut down properly or if it fails for any reason, it must be removed from the browse list. The Browser service handles browser failures.