Knowledge Base

Troubleshooting browser Event ID 8021 and 8032 on master browsers

Article ID: 135404

Article Last Modified on 10/11/2007

APPLIES TO

This article was previously published under Q135404
Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

SUMMARY

This article discusses some of the common causes of Event ID 8021 and Event ID 8032 on a master browser system. The article also provides different methods that you can use to work around the issue.

SYMPTOMS

A computer that runs Microsoft Windows NT or Microsoft Windows 2000 or later operating systems may occasionally log one or more of the following events in the System log.

Event message 1

Event ID: 8021
Source: Browser
Type: Warning
Description: The browser was unable to retrieve a list of servers from the browser master \\CurrentMasterBrowser on the network \Device\Protocol_NetworkAdaptor. The data is the error code.
Data Words:
0000: 00000005

Sample text:
The browser was unable to retrieve a list of servers from the browser master \\SERVER44 on the network \Device\NetBT_Tcpip_{D995825F-F226-49D6-8221-503BE0A9BBAD}. The data is the error code.

Event message 2

Event ID: 8032
Source: Browser
Type: Error
Description: The Browser service has failed to retrieve the backup list too many times on transport \Device\Protocol_NetworkAdaptor. The backup browser is stopping.
Data Words:
0000: 00000005

Sample text:
The Browser service has failed to retrieve the backup list too many times on transport \Device\NetBT_Tcpip_{D995825F-F226-49D6-8221-503BE0A9BBAD}. The backup browser is stopping.

This problem may occur when the following conditions are true:

CAUSE

This problem occurs when one or more of the following is true: Note A virtual network adaptor (NLB/WLBS) could make a system logically multihomed. Also, active Routing and Remote Access or VPN connections on a computer make it multihomed.

Troubleshooting

Typically, these browser events appear every two hours. However, these browser events may not always have a major affect on the system's browser functionality. Use the following guidelines to troubleshoot these events.

WORKAROUND

To work around this problem, use one of the following procedures:
  • Unbind all but one of the TCP/IP subnet transport bindings from the workstation service.
  • Remove all but one of the network cards or remote access connections.
  • At the command prompt, type the following command:

    net stop browser

    Note This option prevents you from receiving computer browse lists from other networks.
After you use one of these procedures, wait at least 10 minutes to see whether the errors still occur. If they do, continue troubleshooting by cross-referencing two pieces of information. First, note the transport that failed in the event log. For example, error 8021 displays a message that is similar to the following:
The browser was unable to retrieve a list of servers from the browser master \\server name on the network \Device\NetBT_driver name. The data is the error code.
The important data is NetBT_driver name. This indicates the protocol and netcard binding, also known as an "endpoint." The potential protocols you may see are as follows:

Nbf_netcard = NetBEUI
NetBT_netcard = TCP/IP (NetBIOS over TCP/IP)
NwlnkIpx = IPX/SPX (NwLink) [will not indicate netcard]
NwlnkNB = NetBIOS over NwLink [will not indicate netcard]

After you have determined the failed protocol endpoint, verify the working status of the Browser service on all installed protocols with the Windows NT resource kit program Browstat.exe. At a command prompt, type the following command:

browstat status

This will enumerate the browser status on all endpoints. Look for the following message under each endpoint:
Browser is NOT active on domain
Ignore data about endpoints that list "NdisWanX," such as Device\NetBT_NdisWan5. These are remote access endpoints, which usually list the error anyway.

You should find a protocol match between these two steps. The next step is to record any important information about the protocol from Protocol Setup in the Network tool in Control Panel. Then, remove the protocol, restart the computer, and see whether the error no longer is logged.

Note Remember to wait at least 10 minutes.
Then, try to reinstall the protocol, to check for the error, and then to reapply the service pack that exists on the current Windows NT installation.

If the error persists after a protocol reinstallation, you may have problems with the network adaptor card. Contact the vendor to see if an updated driver is available or try another network adaptor card.

To permanently prevent multihomed Windows-based servers from becoming browser servers, use one of the following methods.
Method 1: Use Microsoft Management Console (MMC) or Control Panel
Windows NT 4.0
  1. Click Start, point to Settings, click Control Panel, and then double-click Services.
  2. Click Computer Browser, click Properties, and then click Manual.
  3. Click OK, click Close, and then restart the browser service or restart the computer.
Windows 2000 or later operating systems
  1. Click Start, click Run, and then type services.msc
  2. Right-click the Computer Browser service, and then click Properties.
  3. In the Startup type list, select Manual, and then click OK.
  4. Right-click the Computer Browser service, and then click Restart.
Method 2: Use Registry Editor
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

Windows 2000
  1. Click Start, click Run, type Regedt32, and then click OK.
  2. Locate the following registry entry:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\

  3. Change the value to of MaintainServerList to No.
  4. Restart the computer.
Windows NT and Windows XP
  1. Click Start, click Run, type Regedt32, and then click OK.
  2. Locate the following registry entry:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\

  3. Change the value to of MaintainServerList to false.
  4. Restart the computer.
If the value of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\ MaintainServerList is No, this server is not a browser.

If the value of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\ MaintainServerList is Yes, this server becomes a browser.

The Computer Browser service tries to contact the master browser to obtain a current browser list. If the Computer Browser service cannot find the master browser, it forces an election and is a candidate to become the master browser. Additionally, setting MaintainServerList to Yes causes an election to be generated when the browser starts.
Method 3: Use the Service Controller (SC) utility
You can use the command-line Service Controller utilities Sc.exe and Netsvc.exe to switch the start value of a service. You can find these utilities in the Windows 2000 Resource Kit You can also use these utilities to remotely start and stop a service.

To disable the Browser service on a remote system type the following command at a command prompt:

SC \\ServerName config Browser start= disabled

Note The option name includes an equal sign followed by a blank character.

For more information about the Sc.exe tool, see the Sc-dev.txt file. This file is located in the Windows 2000 Resource Kit.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

The Computer Browser service maintains an updated list of computers on the network. The service also supplies this list to computers. The browser maintains all its server information on a per-transport basis. A transport is the physical network card bound to a protocol. The browser service depends on the workstation service to collect a list of servers over all installed transport and adaptor combinations.

There is a common misunderstanding about when the Computer Browser service is needed. You should run this service only on Windows-based systems that perform the role of a browser: The Workstation service (redirector) on your computer is responsible for obtaining the list of servers and domains in the network.

The term "physically multihomed" refers to having more than one network interface. The term "logically multihomed" refers to having more than one IP address on one interface.

The browsing role can be disabled on a transport basis, as described here, or on an adaptor basis by using the following registry subkey:

HKEY_LOCAL_MACHINE\CurrentControlSet\Services\Browser\Parameters\UnboundBindings


Data type: REG_MULTI_SZ
String Value:
NetBT_name of network adaptor driver to be disabled (on Windows NT 4.0 systems)
NetBT_Tcpip_{adaptor GUID} (On Windows 2000 and later systems)

If you have more than two network adaptors in the multihomed Windows based server, type each driver instance that you want to disable on a separate line in the multi-string field.

Caution Follow these steps to unbind a transport from the browser only if you are sure that this transport is no longer required on the browser computer because of redundancy. Make sure to back up the registry first.

To determine the transport number to be unbound, run the net config workstation command, the net config workstation command, the ipconfig/all command, and the browstat unbindtransport number command at a command prompt. To do this, use the following procedure.

Note The Browstat utility is included in the Windows 2000 Support Tools. For more information the Windows 2000 Support Tools, click the following article number to view the article in the Microsoft Knowledge Base:

301423 How to install the Windows 2000 Support Tools to a Windows 2000 Server-based computer

  1. At a command prompt, type net config workstation, and then press ENTER.

    The output on Windows 2000 or later operating systems will be similar to the following:
    Workstation active on
        NetbiosSmb (000000000000)

    
        NetBT_Tcpip_{adaptor GUID} (MAC Address)
        NetBT_Tcpip_{adaptor GUID} (MAC Address)
        NetBT_Tcpip_{adaptor GUID} (MAC Address)
        NetBT_Tcpip_{adaptor GUID} (MAC Address)
  2. At a command prompt, type Ipconfig/all, and then press ENTER.
    The output will show the MAC address for each adaptor:
    Physical Address. . . . . . . . . : 00-02-A5-44-7C-E5


    Now you have determined an association of the MAC address for a specific adaptor together with the transport (device\protocol_GUID) for the browser service.

    Note A Netdiag output shows the association of the MAC address (Physical Address), and GUID for a specific adaptor. It also shows the list of transports that are currently bound to the browser.
  3. At the command prompt, type browstat dumpnet, and then press ENTER.
    This command will list the transports (device/protocol_GUID) that are bound to the computer browser service.

    The output on Windows 2000 or later operating systems will be similar to the following: 
    List of transports currently bound to the browser

    
1 \Device\NetBT_Tcpip_{A5CC1CF0-B511-48B5-84C2-AB2FABD39EFD}
     
    
2 \Device\NetBT_Tcpip_{4D6B03BC-1539-46C3-A10D-C5C8E5D25A4B}
     
    
3 \Device\NetBT_Tcpip_{D995825F-F226-49D6-8221-503BE0A9BBAD}
     
    
4 \Device\NetBT_Tcpip_{C9FAA151-E451-4B54-8C75-0EB2F77CCB5F}


    Note the number that appears in front of the transports (\Device\protocol_GUID). Select the one for the transport that you want to unbind.
  4. At the command prompt, type the following at a command line and then press ENTER.

    Note transport_number is the number that comes before the transport of the output in step 3, and the transport has the format of device\protocol_GUID.

    browstat unbind transport_number

    This command unbinds the \Device\NetBT_Tcpip_{4AA35768-983C-4A7C-B266-357BCB4BB160} from the browser service.
  5. To verify that the procedure worked correctly, type browstat dumpnet at a command prompt, and then press ENTER.
  6. To display the status of a domain, type browstat status at the command prompt, and then press ENTER.

The Browstat utility has the following additional commands:
Usage: browstat Command [Options | /HELP] Where Command is one of the following:
ELECT ( EL) - Force election on remote domain
GETBLIST ( GB) - Get backup list for domain
GETMASTER ( GM) - Get remote Master Browser name (by using NetBIOS)
GETPDC ( GP) - Get PDC name (by using NetBIOS)
LISTWFW (WFW) - List WFW servers that are actually running browser
STATS (STS) - Dump browser statistics
STATUS (STA) - Display status about a domain
TICKLE (TIC) - Force remote master to stop
VIEW ( VW) - Remote NetServerEnum to a server or domain on transport
DUMPNET ( DN) - Display the list of transports bound to browser

There is an additional Browstat command option:

browstat unbind /help

Usage: browstat unbind transport [EmulatedDomain] Unbind a transport from the browser.

Technical support for x64-based versions of Microsoft Windows

Your hardware manufacturer provides technical support and assistance for x64-based versions of Windows. Your hardware manufacturer provides support because an x64-based version of Windows was included with your hardware. Your hardware manufacturer might have customized the installation of Windows with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your x64-based version of Windows. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site:

http://www.microsoft.com/windowsxp/64bit/default.mspx

For product information about x64-based versions of Microsoft Windows Server 2003, visit the following Microsoft Web site:

http://www.microsoft.com/windowsserver2003/64bit/x64/default.mspx

REFERENCES

For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:

102878 Information on browser operation

117633 How browsing browsing over a multi-subnet TCP/IP network works in a domain and in a workgroup

133241 Browsing domain master browsers w/ multiple NICs and protocols

136712 Common questions about browsing with Windows

176321 Unable to resolve NetBIOS names through PPTP connection

180094 How to write an Lmhosts file for domain validation and other name resolution issues

188305 Troubleshooting the Microsoft Computer Browser service

181774 Multihomed issues with Windows NT

191611 Symptoms of multihomed browsers

197991 How to configure WLBS using multiple network interface cards

197992 How to configure WLBS using a single network interface card

224834 Setting filter to capture view only browser frames in network monitor

231312 Computer name missing in the Browsing list when server comment more than 48 characters

246261 How to use the RestrictAnonymous registry value in Windows 2000

254527 Browse list problems when File and Print Sharing is not installed

314872 Browse list issues on servers and clients include error messages about Event ID 8032 and inability to browse

278431 Using teaming adapters with network load balancing may cause network problems

301423 How to install the Windows 2000 Support Tools to a Windows 2000 Server-based computer

318232 The "browstat.exe status" command does not return a server list

325487 How to troubleshoot network connectivity problems

166819 Using Sc.exe and Netsvc.exe to control services remotely

818092 Description of NetBIOS Browsing Console (Browcon.exe)

830578 NBLookup.exe command-line tool


Additional query words: tcpip multi-homed multi homed Winx64 Windowsx64 64bit 64-bit

Keywords: kbbug kbnetwork kbprb KB135404


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