Active Directory Users and Computers may stop responding when you use Active Directory Users and Computers on a server that is not running Exchange Server 2003 to change a user's proxy address

When you use Active Directory Users and Computers on a server that is not running Microsoft Exchange Server 2003 to change a user's proxy address, Active Directory Users and Computers may stop responding.

This problem occurs if the first Exchange server on the Lightweight Directory Access Protocol (LDAP) query list is in a remote site. Active Directory Users and Computers uses the first Exchange server on the LDAP query list to change the user's proxy address. If the first server on the LDAP query list is in a remote site, Active Directory Users and Computers may stop responding.

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.

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

Because of file dependencies, this software update requires Microsoft Exchange Server 2003 Service Pack 1.

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

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.After you install this hotfix, you must configure a new registry entry to apply this hotfix. To configure the new registry entry, follow these steps:

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeMGMT\Parameters
3. On the Edit menu, point to New, and then click String Value.
4. Name the new registry entry "Preferred SA Server".
5. Right-click Preferred SA Server, and then click Modify.
6. In the Value data box, type server_name, and then click OK.
   
   In this value, server_name is the name of the Exchange server that you want Active Directory User and Computers to use.
7. Close Registry Editor.

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

After you apply this hotfix, when Active Directory Users and Computers tries to find an Exchange server, it checks whether the Exchange server that you specified in the Preferred SA Server registry entry is available. If this Exchange server is not available, Active Directory Users and Computers uses an LDAP query to obtain a server list. Active Directory Users and Computers selects a server from this list.

Notes

• This hotfix will have no effect if you install this hotfix on an Exchange server.
• The hotfix and registry change should be made on the member server or the remote client computer that is running the Microsoft Exchange version of Active Directory Users and Computers (Microsoft Exchange Management Tools).