How to avoid Master Browser errors, MRxSmb Event ID 8003

Browser election messages and locked accounts might have some similiar dodgy network connectivity root-cause, but they're not related.

Here's a decent article about troubleshooting the Computer Browser service that's causing your browser election messages: http://support.microsoft.com/kb/188305

As far as the locked user accounts go, I'd suspect that the user has either a cached credential somewhere (wireless Ethernet authentication via PEAP, the account being used as a service user context, /SAVECREDS on a client computer, etc) that has an old password specified.

Troubleshooting account lockout isn't too fun. Have a look at Microsoft's article here for starts: http://technet.microsoft.com/en-us/library/cc773155(WS.10).aspx You need to have the right amount of security logging enabled on your domain controller computers to correlate the lockouts with real-world events (starting a given computer up, starting a service, etc). There are some tools that can help collect the event logs from multiple domain controllers and aggregate them to find the cause of the account lockouts (see http://www.microsoft.com/downloads/details.aspx?FamilyId=7AF2E69C-91F3-4E63-8629-B999ADDE0B9E) since the events will be distributed across the security logs on, potentially, all domain controller computers.

The long-and-short of account lockout troubleshooting is that you need to turn up your security auditing and start researching what's happening in the real world when the lockout event occurs.

ok it would appear the problem is resolved after uninstalling KB968389 (ref) and then reinstalling again. this has had me stumped for a few months, i would never have guessed it was NTLM related...

to quote:

If you capture network traces while trying to access shared folders, you may see a response of Error, Code =(13) STATUS_INVALID_PARAMETER from the server for the session setup:

192.168.0.2 192.168.0.1 SMB:C; Session Setup Andx, NTLM AUTHENTICATE MESSAGE, Workstation: WRK001

192.168.0.1 192.168.0.2 SMB:R; Session Setup Andx - NT Status: System - Error, Code = (13) STATUS_INVALID_PARAMETER

This error code means that there is an issue with NTLM authentication. The update in KB 968389 introduces a new feature that enhances protection and handling of credentials when authenticating network connections by using Integrated Windows Authentication.

This behavior can occur if the update discussed in KB 968389 did not install properly. To correct the issue, please uninstall the update completely and then reboot the server. After the restart, you should find that the symptoms no longer occur. Reinstall the update from KB 968389 and restart the server again. The issue should not re-occur. You should be able to access all shares successfully locally and remotely.