Event ID 8146 is logged in the application log every five minutes after the Exchange 2003 SP1 MSADC component experiences LDAP communication problems

If you configure one or more connection agreements between a computer that is running Microsoft Exchange Server 2003 Service Pack 1 (SP1) and Active Directory directory services, the following symptoms occur:

• The Active Directory Connector (ADC) may stop processing the Recipient Connection Agreement.
• An event that is similar to the following is logged in the application log every five minutes:

  
  Event Type: Error
  Event Source: MSADC
  Event Category: Replication
  Event ID: 8146
  Date: 9/3/2004
  Time: 11:57:51 AM
  User: N/A
  Computer: ComputerName
  Description:
  An operation on server ComputerName returned [0xc] Unavailable Critical Extension. ConnectionAgreementName has stopped.

This problem occurs because the Microsoft Active Directory Connector (MSADC) component cannot use the Lightweight Directory Access Protocol (LDAP) version 3 protocol to communicate with Active Directory after it tries to use the LDAP version 2 protocol.

By default, the MSADC uses LDAP version 3 to communicate with Active Directory. For backward compatibility reasons, MSADC may try to use an earlier version of LDAP if it experiences problems during the communication session.

However, earlier versions of LDAP do not support some critical LDAP extensions that are required by MSADC. The event message that is mentioned in the "Symptoms" section is logged in the application log when MSADC tries to use those extensions when it communicates by using LDAP version 2.

When you restart the MSADC service, the MSADC component uses LDAP version 3 to communicate with Active Directory.

Service pack information

To resolve this problem, obtain the latest service pack for Exchange Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

A supported hotfix is 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 software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if 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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

No prerequisites are required.

Restart requirement

You do not have to restart your computer after you apply this software update.

Hotfix replacement information

This hotfix does not replace any other software updates.

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 tool in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Exchange Server 2003 Service Pack 2.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base: For additional information, click the following article number to view the article in the Microsoft Knowledge Base: