You may find this message in your event log listed as an Error that says something along the lines of:

“The master browser has received a server announcement from the computer XXX that believes that it is the master browser for the domain on transport NetBT_Tcpip_XXX-. The master browser is stopping or an election is being forced.“

Firstly, don’t panic. This is typically a network configuration issue and is not really an error (the allocation of Warnings and Errors in the event log are sometimes frustrating!) as it is Windows networking trying to do it’s job. When two or more Windows computers are connected together they form a network and Windows tries to maintain a list of connected machines to make them easier to find. The difficulty is deciding which machine to maintain this list.

If you have a dedicated server on the network then you can often stop the computer browser service on the client machines by going into control panel->administrative tools->services then double-clicking on the “Computer Browser” option then clicking on the “Stop” button (or disable it altogether – you can always re-enable it if you run into trouble!).

If however you don’t have a dedicated machine for handling these messages then it might be best to do nothing and allow windows to do its job.

Another way this can happen is if you are connected to a remote network and the device that connects the two networks together (typically a router) is forwarding UDP broadcast packets – in which case machines on the remote network may get confused when they see your machine (and vice versa) – on a number of routers you may be able to stop this traffic passing between the networks – but do this with caution as software or services you are connecting to may need to send that sort of traffic over the network. Microsoft have a useful outline of this problem: 8003 browsing errors with UDP forwarding