Microsoft KB Archive/929439

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Article ID: 929439

Article Last Modified on 10/25/2007


  • Microsoft Exchange Server 2003 Standard Edition
  • Microsoft Exchange Server 2003 Enterprise Edition

Important This article contains information about how to modify the registry. Make sure that you 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


A MAPI program may not obtain a referral server when the global catalog server to which the MAPI program points is shut down. When this occurs, all address book lookup calls that are made by the MAPI program fail. Additionally, the MAPI_E_NETWORK_ERROR error code is returned until the MAPI program is restarted.

This problem occurs if the following conditions are true:

  • The MAPI program runs as a service on a server that has components of Microsoft Exchange 2003 Service Pack 1 (SP1) installed.
  • The MAPI program uses the MAPI address book provider that is included in Exchange 2003.
  • The global catalog reconnect logic is deployed by setting the PR_PROFILE_ABP_ALLOW_RECONNECT flag in the profile of the MAPI program.


During the shutdown of a global catalog server, when the Exchange 2003 server tries to locate a new global catalog server, the Kerberos Key Distribution Center (KDC) service returns the KDC_ERR_PRINCIPAL_UNKNOWN error code to the Exchange 2003 server. Then, the Exchange 2003 server passes a failed credentials error back to the MAPI program. This behavior causes the connection to stop using process credentials and to enter a user credentials state. However, the user credentials state will fail when the MAPI program is running as a service. This failure occurs because the MAPI program cannot prompt for credentials.


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 the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

You must create the EMSAB_UserAuth_Credentials registry entry on the Exchange 2003 server where the hotfix is installed for this hotfix to work. With the EMSAB_UserAuth_Credentials registry entry set to the value 1, the MAPI provider will never enter the user credential state. When the global catalog server is still shutting down, MAPI clients that have this registry entry will continue to obtain the MAPI_E_NETWORK_ERROR error code. However, as soon as the global catalog server has finished shutting down, and the Exchange 2003 server has established a connection with a new global catalog server, the MAPI client will obtain the expected MAPI_E_END_OF_SESSION error code.

Important When this registry key is set on an Exchange 2003 server with the hotfix installed, the user credential state cannot be entered by MAPI clients that are running on the server. This hotfix will prevent the MAPI clients that require user interface from connecting across domain boundaries, where it is expected that users can be prompted for credentials. Make sure that you do not set the registry entry on Exchange 2003 servers when the UI prompt for credentials is desired by MAPI clients that are running on the servers. This hotfix does not alter the behavior of Exchange 2003 as a MAPI server. Also, it does not affect Outlook clients or any other MAPI clients that are running on other computers in which the hotfix and registry key have not been applied.

To set the EMSAB_UserAuth_Credentials registry value, follow these steps:

  1. Click Start, click Run, type regedit, and then click OK.
  2. Locate the following registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Exchange Provider

  3. On the Edit menu, point to New, and then click DWORD Value.
  4. In the Details pane, type EMSAB_UserAuth_Credentials, and then press Enter.
  5. Right-click EMSAB_UserAuth_Credentials, and then click Modify.
  6. In the Edit DWORD Value dialog box, click Decimal in the Base area.
  7. In the Value data box, type 1, and then click OK.
  8. Exit Registry Editor.

Hotfix information

A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:


Because of file dependencies, Microsoft Exchange Server 2003 Service Pack 2 (SP2) must be installed on the server before you apply this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

836993 How to obtain the latest service packs for Exchange Server 2003

Restart requirement

You do not have to restart your computer after you apply this hotfix. However, the following services are automatically restarted when you apply the hotfix:

  • Microsoft Exchange Information Store service
  • Microsoft Exchange MTA Stacks
  • Microsoft Exchange System Attendant

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

File name File version File size Date Time Platform
Emsabp32.dll 6.5.7652.15 173,568 22-Feb-2007 02:55 x86


For more information about the MAPI application global catalog reconnect logic, visit the following Microsoft Web site:


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

Keywords: kbexchdev kbqfe kbexpertiseinter kbhotfixserver KB929439