Fix Master Browser (MRXSMB) Event ID 8003

The Event ID 8003 (Master Browser) error messages, on some Windows Server systems (specially older ones) is probably one of the most searched on this environments due to the fact that this event is linked to WINS (the predecessor of DNS on Windows systems) and the Computer Browser system service (still available even on newer Windows 10 clients and Windows Server).

The error is usually seen as the following (in the Event Viewer):

The master browser has received a server announcement from the computer  that believes that it is the master browser for the domain on transport NetBT_Tcpip_{B7545DFC-BA6C-4712-81. The master browser is stopping or an election is being forced.

Common steps that can be done to address this error (not a difficult one to fix) are the following:

  • Look at the System Event log on your server and look for the error 8003. Within that log, identify the “computer” that is announcing itself as a master browser.
  • Go on to the computer identified in, go to the Services Administration panel. You can usually find this by going to Control Panel -> Administrative Tools -> Services.
  • Once you have Services open, look for an entry called Computer Browser. If that service is Started, you have found your culprit: just disable it if you do not user Network Browser on you servers and clients to search Shared Folders.

  • Double click on the Computer Browser service to edit it. Stop the service and then change the type to Disabled (from either Manual or Automatic). Click OK to apply your changes.
  • That should have resolved the issue. You should check your main servers event logs periodically to be sure that the error does not show up.
  • If still not fixed, check the following registry value on the computer: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\IsDomainMaster. Ensure that it is set to false. You probably have to reboot the machine to make the change take place.

Computer Browser Service

Browser service or Computer Browser Service is a feature of Microsoft Windows to let users easily browse and locate shared resources in neighboring computers. This is done by aggregating the information in a single computer 'Browse Master' (or 'Master Browser'). All other computers contact this computer for information and display in the Network Neighborhood window.

Computer Browser Service provides backwards compatibility for Windows versions that don't use Active Directory. For My Network Places, Windows Explorer, and the net view command, Computer Browser is still needed.

On Windows Active Directory domains is safe to disable, using a GPO (Group Policy Object), the Computer Browser service (if you are sure that this will not impact any legacy application or other software on your environments) on all domain server and client systems.