How to apply Exchange service packs and hotfixes

This step-by-step article describes how to apply Exchange service packs and hotfixes.

Make sure that you consider the effects of applying a service pack or hotfix. After you read the information in this article, thoroughly test the service pack or hotfix in your laboratory environment before you deploy it on production servers.

Microsoft Exchange Server 2003

Before you deploy an Exchange 2003 service pack or hotfix, carefully consider the following important notes, and then see the different sections in this article for information about your specific configuration.

Important notes

• Always create a full backup of all Exchange databases and create a backup of the system state on the Exchange server and the domain controllers in the domain before you apply a service pack. If you must roll back to the earlier version of Exchange, you may have to remove and reinstall Exchange to its original state, including the system state, on the Exchange computer and domain controller that existed before you installed the Exchange service pack.
• Always read the release notes for service packs before you apply a service pack. The service pack may apply changes that relate to your specific environment.
• After you install a service pack for Exchange 2003, you cannot restore online backups to versions of Exchange Server 2003 that are earlier than the current service pack. For example, you cannot restore an Exchange Server 2003 Service Pack 2 database to a server that is running Exchange Server 2003 Service Pack 1 or earlier versions of Exchange Server. Because of this behavior, always create a full backup of all Exchange Server databases after you apply a service pack.
• The Active Directory Connector (ADC) is not automatically updated when you install an Exchange 2003 service pack. The ADC service pack has its own Setup program in the ADC\I386 folder of the Exchange 2003 service pack. This is true although the ADC is installed on the same server as Exchange 2003. For more information about the ADC, click the following article number to view the article in the Microsoft Knowledge Base:
  306505

  (http://support.microsoft.com/kb/306505/ )

  The Active Directory Connector upgrade does not succeed if certain files are in use
• If you deployed the ADC service with custom versions of the Local.map file and the Remote.map file, you must make the same customizations to the service pack version of the ADC service before you upgrade.
  
  As a safeguard, use a tool such as LDP to export the contents of the msExchServer1SchemaMap attribute and the msExchServer2SchemaMap attribute before you upgrade the ADC service. If you want help with this process, contact Microsoft Product Support Services (PSS).
  
  Warning If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows 2000 Server, Microsoft Windows Server 2003, Microsoft Exchange 2000 Server, Microsoft Exchange Server 2003, or both Windows and Exchange. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk. For more information about the LDP Utility, click the following article numbers to view the articles in the Microsoft Knowledge Base:
  255602

  (http://support.microsoft.com/kb/255602/ )

  Browsing and querying using the LDP utility
  260745

  (http://support.microsoft.com/kb/260745/ )

  Using the LDP utility to modify Active Directory object attributes
• Before you install a service pack, exit any antivirus programs that are running on the server. Stop any non-essential services or exit any non-essential programs on the server. These services and programs may be third-party programs such as file-level antivirus programs, backup services, the SNMP service, monitoring programs such as server monitors, or Microsoft Performance Monitor.
  
  Note If a service or a program interferes with the hotfix installation, the hotfix may not be installed. When this occurs, the hotfix log may include the following text:
  FileInUse:: Added to Filelist:
  Multiple instances of the Setup program, Update, or even Xcopy can also prevent a service pack from installing. You can use Task Manager to see whether one or more of these programs are running on the server before you apply a service pack.
• After an Exchange service pack has been installed, it cannot be uninstalled. If you must revert to the version of Exchange that was running before the service pack was installed, you will have to remove Exchange from the computer, reinstall Exchange, and then restore the Exchange databases from a backup.

Non-clustered server

When you install a service pack on an Exchange computer that is not clustered, just run the service pack or the hotfix. This procedure temporarily stops the Exchange services, and you may have to restart the computer. For example, you may have to restart the computer if you applied the service pack through a terminal services session.

If the Exchange Server 2003 organization uses a front-end and back-end architecture, you must upgrade your front-end servers before you upgrade your back-end servers.

If you run front-end servers in a load-balanced configuration, try to upgrade all front-end servers at the same time. To do this, take all your front-end servers offline, upgrade each server, and then bring the servers back online. When you upgrade all front-end servers to the service pack at the same time, you minimize the chances of having errors in mobile clients. Mobile clients may receive synchronization key errors if some front-end servers are running SP1 or SP2, but others are running the original release version of Exchange Server 2003. These errors occur when client requests are redirected from SP1 or SP2 to released front-end servers. These errors will stop occurring after all load-balanced front-end servers are running the same version of the service pack.

Clustered server

Important You do not have to restart the computer after you install an Exchange hotfix or service pack that affects a cluster server. However, you must manually shut down the Cluster service and all the dependent resources before you install the hotfix or the service pack. To manually shut down the Cluster service and all the dependent resources, move the cluster group or groups from the cluster node where you want to install the hotfix or the service pack. Then, stop the Cluster service on that cluster node. The Microsoft Exchange Information Store service is automatically stopped and then restarted when you install the hotfix or the service pack.

To upgrade a cluster to an Exchange 2003 service pack, you must first run the Exchange 2003 Service Pack Setup program to upgrade the nodes of the cluster, and then use Cluster Administrator to upgrade the Exchange virtual servers. We recommend that you upgrade one Exchange cluster node at a time.

When you upgrade each node, we recommend that you move the Exchange Virtual Server from the node that you are upgrading to another node. This procedure lets users access their e-mail through the relocated Exchange Virtual Server during the Exchange 2003 service pack upgrade process.

You may want to upgrade a Windows 2000-based server cluster that is running Exchange 2000 Server to a Windows Server 2003-based server cluster that is running Exchange Server 2003 by using the clean installation method. When you do this, make sure that you upgrade the Exchange Virtual Server before you apply any service packs. For more information about this upgrade method, click the following article number to view the article in the Microsoft Knowledge Base: Note The following example refers to a two-node server cluster. However, the example also applies to multi-node clusters for Exchange Server 2003.

To help clarify these steps, the sample server cluster that is described here is a two-node server cluster, and the cluster nodes are named "Cluster Node 1" and "Cluster Node 2." The following example also uses an Exchange virtual server that is named "Exchange Virtual Server 1."

To install a service pack or a hotfix for Exchange 2003 on a server cluster, follow these steps:

1. If you are running Microsoft Windows Server 2003, you must apply the hotfix that is described in the following Microsoft Knowledge Base article:
   831464

   (http://support.microsoft.com/kb/831464/ )

   FIX: IIS 6.0 compression corruption causes access violations
   
   Note You must restart your computer after you apply this hotfix.
2. Move "Exchange Virtual Server 1" to "Cluster Node 1." To do this, right-click "Exchange Virtual Server 1" in the console tree under Groups, and then click Move Group. The move is complete when the Owner column for the "Exchange Virtual Server 1" resources changes from “Cluster Node 2” to “Cluster Node 1”.
   
   Note You must do this to make sure that there are no Exchange virtual servers that are running on “Cluster Node 2.” You must also make sure that the cluster resource group is not running on “Cluster Node 2.”
   
   In a multi-node scenario, you must make sure that each node on which you install the service pack is not running either Exchange Virtual Server or the cluster resource group.
   
   
3. In the Cluster Administrator tool, right-click the “Cluster Node 2” object, and then click Stop Cluster Service.
4. Install the Exchange 2003 Service Pack on "Cluster Node 2." For more information about how to obtain Exchange 2003 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
   836993

   (http://support.microsoft.com/kb/836993/ )

   How to obtain the latest service packs for Exchange Server 2003
5. After you finish installing the Exchange 2003 service pack, click Yes if you are prompted to restart the computer.
   
   Note You do not have to restart the computer if you do not receive a prompt.
6. After "Cluster Node 2" has restarted, log on, and then start the Cluster Administrator tool. To do this, click Start, point to Administrative Tools, and then click Cluster Administrator.
7. Take all the "Exchange Virtual Server 1" resources offline except the following resources:
   • The IP Address resource
   • The Physical Disk resource or resources
   • The Network Name resource
   Note To take a resource offline, right-click the resource, and then click Take Offline.
8. In the Cluster Administrator tool, right-click the “Cluster Node 2” object, and then click Start Cluster Service.
9. Move the Exchange virtual server to the cluster node in which you installed the Exchange 2003 service pack. In this example, move "Exchange Virtual Server 1" to "Cluster Node 2." To do this, right-click the group, and then click Move Group.
10. On "Cluster Node 2", start the Cluster Administrator tool.
11. If you applied a hotfix, go to step 12. If you did not apply a hotfix, expand the cluster, expand Groups, right-click the group that contains "Exchange Virtual Server 1," and then click Upgrade Exchange Virtual Server.
12. After "Exchange Virtual Server 1" is upgraded successfully, bring the Exchange resources online on "Cluster Node 2."
    
    Note After you bring the cluster resources online on the upgraded "Cluster Node 2," you cannot move them to "Cluster Node 1" until you upgrade "Cluster Node 1" to the same Exchange 2003 service pack.
13. In the Cluster Administrator tool, right-click the “Cluster Node 1” object, and then click Stop Cluster Service.
14. On "Cluster Node 1," install the Exchange 2003 service pack, and then click Yes if you are prompted to restart the computer.
    
    Note You do not have to restart the computer if you do not receive a prompt.
15. Start the Cluster Administrator tool. In the Cluster Administrator tool, right-click the “Cluster Node 1” object, and then click Start Cluster Service.
16. If you are in a multi-node scenario, repeat steps 1 through 15 to upgrade the other nodes and other Exchange virtual servers to the Exchange 2003 Service Pack.
    
    
17. Make sure that you can successfully failover "Exchange Virtual Server 1" from one cluster node to the other.
18. Verify the version of Exchange that is installed. To do this, follow these steps:
    • Start Exchange System Manager.
    • Expand Servers, right-click the name of the clustered Exchange server, and then click Properties.
    • Click the General tab. Information that is similar to the following information appears:
      Version 6.5 (Build 7226.6: Service Pack 1)
      Version 6.5 (Build 7638.2: Service Pack 2)

Troubleshooting

The Upgrade Virtual Server option does not appear

The Upgrade Virtual Server option does not appear when you right-click the Exchange virtual server. In this scenario, the Exchange virtual server resources may not come online, and an event that is similar to the following event appears in the Application log in Event Viewer:This issue may occur if you have evicted the cluster node from the server cluster and then re-added the cluster node to the server cluster. To resolve this issue, run the Exchange 2003 Setup program, and then select the Reinstall option to reinstall Exchange 2003 on that cluster node.

You receive an error message when you try to upgrade the Exchange virtual server

When you try to upgrade the Exchange virtual server, you may receive an error message that is similar to the following error message:This issue occurs when either of the following conditions is true:

• You try to upgrade the Exchange virtual server when the Exchange virtual server resource is hosted on a cluster node that has not been upgraded to Exchange 2003 SP1.
• You try to upgrade the Exchange virtual server by using the Cluster Administrator tool from a cluster node computer that has not been upgraded to Exchange 2003 SP1.

To resolve this issue, make sure that all the following conditions are true:

• The Exchange virtual server is hosted on a cluster node that is running Exchange 2003 SP1.
• The Exchange System Attendant resource is offline.
• Only the following resource types are online in the Exchange virtual server group:
  • IP Address
  • Network Name
  • Physical Disk
• The Distributed Transaction Coordinator resource type is online.

Small Business Server 2003

The version of Exchange 2003 that is included with Small Business Server 2003 is a typical version of Exchange 2003. Therefore, you do not have to make special arrangements before you apply Exchange 2003 service packs. When you install a service pack on the version of Exchange 2003 that is included with Small Business Server 2003, just run the service pack or the hotfix. This temporarily stops the Exchange services, and may require that you restart the computer. For example, you may have to restart the computer if you apply the service pack through a terminal services session.

Microsoft Exchange 2000 Server

Before you deploy an Exchange 2000 service pack or hotfix, carefully consider the following important notes, and then see the different sections in this article for information about your specific configuration.

Important notes

• Always create a full backup of all Exchange databases and create a backup of the system state on the Exchange server and the domain controllers in the domain before you apply a service pack. If you must roll back to the earlier version of Exchange, you may have to remove and reinstall the Exchange server to its original state, including the system state, on the Exchange server and domain controller that existed before the Exchange service pack was installed.
• Always read the release notes for service packs before you apply a service pack. The service pack may apply changes that relate to your specific environment.
• After you install a service pack for Exchange 2000, you cannot restore online backups that you created by using versions of Exchange that are earlier than the current service pack. Therefore, always create a full backup of all Exchange databases after you apply a service pack.
• The installation of an Exchange 2000 service pack does not automatically update the Active Directory Connector (ADC). The ADC service pack has its own Setup program in the ADC\I386 folder of the Exchange 2000 service pack. This is true although the ADC is installed on the same server as Exchange 2000. For more information about the ADC, click the following article number to view the article in the Microsoft Knowledge Base:
  306505

  (http://support.microsoft.com/kb/306505/ )

  The Active Directory Connector upgrade does not succeed if certain files are in use
• If you deployed the ADC service with custom versions of the Local.map and Remote.map files, you must make the same customizations to the service pack version of the ADC service before you upgrade. For more information about how to upgrade the ADC, click the following article number to view the article in the Microsoft Knowledge Base:
  316542

  (http://support.microsoft.com/kb/316542/ )

  Customize ADC before you upgrade to Exchange 2000 Service Pack 3
  As a safeguard, use a tool such as LDP to export the contents of the msExchServer1SchemaMap attribute and the msExchServer2SchemaMap attribute before you upgrade the ADC service. If you require help with this process, contact Microsoft Product Support Services (PSS).
  
  Warning If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows 2000 Server, Microsoft Windows Server 2003, Microsoft Exchange 2000 Server, Microsoft Exchange Server 2003, or both Windows and Exchange. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk. For more information about the LDP Utility, click the following article numbers to view the articles in the Microsoft Knowledge Base:
  255602

  (http://support.microsoft.com/kb/255602/ )

  Browsing and querying using the LDP utility
  260745

  (http://support.microsoft.com/kb/260745/ )

  Using the LDP utility to modify Active Directory object attributes
• Before you install a service pack, exit any antivirus programs that are running on the server. Stop any non-essential services or exit any non-essential programs on the server. These services and programs may be third-party programs such as file-level antivirus programs, backup services, the SNMP service, monitoring programs such as server monitors, or Microsoft Performance Monitor.
  
  Note If a service or a program interferes with the hotfix installation, the hotfix may not be installed. When this occurs, the hotfix log may include the following text:
  FileInUse:: Added to Filelist:
  Multiple instances of the Setup program, Update, or even Xcopy can also prevent a service pack from installing. You can use Task Manager to see whether one or more of these programs are running on the server before you apply a service pack.
• After an Exchange service pack has been installed, it cannot be uninstalled. If you must revert to the version of Exchange that was running before the service pack was installed, you will have to remove Exchange from the computer, reinstall Exchange, and then restore the Exchange databases from a backup.

Non-clustered server

When you install a service pack on an Exchange computer that is not clustered, you only have to run the service pack or the hotfix. This temporarily stops the Exchange services, and you may have to restart the computer. For example, you may have to restart the computer if you apply the service pack through a terminal services session.

If you configure the Exchange 2000 computers as front-end and back-end servers, we recommend that you first install the Exchange 2000 service pack on the front-end servers before you install the service pack on the back-end servers. If you have multiple front-end servers, you do not have to upgrade them all at the same time. In this case, just make sure that you upgrade all the front-end servers before you install the Exchange 2000 service pack on any the back-end servers.

If you install the Exchange 2000 service pack on the front-end servers first, service for Microsoft Outlook Web Access clients is not interrupted. When an Outlook Web Access client connects to an Exchange 2000 computer, the client downloads script files from the front-end server. The script files on front-end servers that have not been upgraded to the Exchange 2000 service pack are incompatible with back-end servers that have been upgraded to the Exchange 2000 service pack. However, the script files on an upgraded Exchange 2000 front-end server are compatible with back-end servers that have not been upgraded to Exchange 2000 service pack. For more information about Exchange 2000 service packs, click the following article numbers to view the articles in the Microsoft Knowledge Base: For more information about multiple setup errors that may occur when you apply service pack 1 to Exchange 2000 Server, click the following article number to view the article in the Microsoft Knowledge Base: For more information about Exchange 2000 front-end and back-end configurations, click the following article numbers to view the articles in the Microsoft Knowledge Base:

Active/Passive clustered server

Important You do not have to restart the computer after you install an Exchange hotfix or service pack that affects a cluster server. However, you must manually shut down the Cluster service and all the dependent resources before you install the hotfix or the service pack. To manually shut down the Cluster service and all the dependent resources, move the cluster group or groups from the cluster node where you want to install the hotfix or the service pack. Then, stop the Cluster service on that cluster node. The Microsoft Exchange Information Store service is automatically stopped and then restarted when you install the hotfix or the service pack.

Apply the Exchange service pack to the passive node of a Microsoft Windows 2000 active/passive cluster first.

For example, if Node A is currently the owner of the Exchange virtual server and the cluster resource group, and Node B is the passive or idle node, follow these steps:

1. Apply the hotfix or service pack to Node B first.
2. Move the Exchange and the cluster resource groups to Node B. As Node B starts the Exchange resources, Exchange databases are upgraded by the new store if you are applying a store hotfix or a service pack.
3. After this process has completed, apply the service pack or hotfix to "Node A" that is now the passive node.
   
   Note Youmust stop the cluster service before the hotfix is installed.

For more information about how to install Exchange 2000 Service Pack 1 on a cluster server, click the following article number to view the article in the Microsoft Knowledge Base:

Active/Active clustered server

Important You do not have to restart the computer after you install an Exchange hotfix or service pack that affects a cluster server. However, you must manually shut down the Cluster service and all the dependent resources before you install the hotfix or the service pack. To manually shut down the Cluster service and all the dependent resources, move the cluster group or groups from the cluster node where you want to install the hotfix or the service pack. Then, stop the Cluster service on that cluster node. The Microsoft Exchange Information Store service is automatically stopped and then restarted when you install the hotfix or the service pack.

When you install a service pack on an Exchange 2000 Active/Active clustered server, move all the Exchange virtual servers to one node of the cluster. You can then apply the service pack to the free node.

For example, if Node A is currently the owner of Exchange Virtual Server 1 and Node B is currently the owner of Exchange Virtual Server 2, follow these steps:

1. Move the Exchange group for Exchange Virtual Server 1 and the cluster resource group from Node A to Node B.
2. Node B is now running both Exchange Virtual Server 1 and Exchange Virtual Server 2. Node B is also running the cluster resource group. Apply the service pack or hotfix to Node A.
3. After this process has completed, move the Exchange groups for both Exchange Virtual Server 1 and Exchange Virtual Server 2 to Node A. Additionally, move the cluster resource group to Node A.
4. Node A starts the Exchange virtual servers, and the Exchange databases are upgraded by the new store if you are applying a store hotfix or a service pack.
5. Node A now runs Exchange Virtual Server 1, Exchange Virtual Server 2, and the cluster resource group. After this process has completed, apply the service pack or hotfix to Node B that is now the passive or idle node.

For more information about how to install Exchange 2000 Service Pack 1 on a cluster server, click the following article number to view the article in the Microsoft Knowledge Base:

Small Business Server 2000

Exchange 2000 that is included with Small Business Server 2000 is a typical version of Exchange 2000. Therefore, you do not have to make special arrangements before you apply Exchange 2000 service packs with Small Business Server 2000. When you install a service pack on the version of Exchange 2000 that is included with Small Business Server 2000, just run the service pack or the hotfix. This temporarily stops the Exchange services and may require that you restart the computer. For example, you may have to restart the computer if you apply the service pack through a terminal services session.

Note Microsoft has released Small Business Server 2000 Service Pack 1 (SP1). This is an integrated Setup program that includes the following:

• Small Business Server 2000 SP1
• Windows 2000 SP3
• Exchange 2000 SP3

For more information about how to obtain the latest Small Business Server 2000 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft Exchange Server 5.5

Before you deploy an Exchange Server 5.5 service pack or hotfix, carefully consider the following important notes, and then see the different sections in this article for information about your specific configuration.

Important notes

• Always create a full backup of all Exchange databases and create a backup of the system state on the Exchange server and domain controllers in the domain before you apply a service pack. If you must roll back to the earlier version of Exchange, you may have to remove and reinstall Exchange to restore the original state, including the system state, that existed on the Exchange computer and domain controller before you installed the Exchange service pack.
• Always read the release notes for service packs before you apply a service pack. The service pack may apply changes that relate to your specific environment.
• Always run the Performance Optimizer program after you install a service pack on Exchange Server 5.5.
• After you install a service pack for Exchange Server 5.5, you may not be able to restore online backups that you created by using versions of Exchange that are earlier than the current service pack. Therefore, always create a full backup of all Exchange databases after you apply a service pack.
• The installation of an Exchange Server 5.5 service pack does not automatically update additional components such as the InterOrg replication tool or Mailbox Manager. You must run separate installation procedures or programs to update these components:
  • The Mailbox Manager software is available on the service pack CD in the ENG\SERVER\SUPPORT\Mbmngr folder.
  • The InterOrg Replication utility and its additional documentation are available on the service pack CD in the ENG\SERVER\SUPPORT\EXCHSYNC folder.
    
    For more information about how to update these components, see the Exchange Server 5.5 Service Pack release notes.
• Before you install a service pack, exit any antivirus programs that are running on the server. Stop any non-essential services or exit any non-essential programs on the server. These services and programs may be third-party programs such as file-level antivirus programs, backup services, the SNMP service, monitoring programs such as server monitors, or Microsoft Performance Monitor.
  
  Note If a service or a program interferes with the hotfix installation, the hotfix may not be installed. When this occurs, the hotfix log may include the following text:
  FileInUse:: Added to Filelist:
  Multiple instances of the Setup program, Update, or even Xcopy can also prevent a service pack from installing. You can use Task Manager to see whether one or more of these programs are running on the server before you apply a service pack.
• After an Exchange service pack has been installed, it cannot be uninstalled. If you must revert to the version of Exchange that was running before the service pack was installed, you will have to remove Exchange from the computer, reinstall Exchange, and then restore the Exchange databases from a backup.

Non-clustered server

When you install a service pack on an Exchange Server 5.5 computer that is not clustered, just run the service pack or the hotfix. This temporarily stops the Exchange services, and you do not have to restart the computer.

Clustered server

Important You do not have to restart the computer after you install an Exchange hotfix or service pack that affects a cluster server. However, you must manually shut down the Cluster service and all the dependent resources before you install the hotfix or the service pack. To manually shut down the Cluster service and all the dependent resources, move the cluster group or groups from the cluster node where you want to install the hotfix or the service pack. Then, stop the Cluster service on that cluster node. The Microsoft Exchange Information Store service is automatically stopped and then restarted when you install the hotfix or the service pack.

On a clustered Exchange Server 5.5 computer, apply a service pack or hotfix to the active node first.

For example, if Node A is currently the owner of Exchange virtual server and Node B is the passive (idle) node, follow these steps:

1. Install the service pack on the primary (active) node, Node A.
   
   Important Do not fail over or move the Exchange Server group to the secondary node.
2. Install the service pack on the secondary (passive or idle) node, Node B.

Note If you update an earlier version of Exchange Server on clustered computers, the installation program stops the Exchange Server services. When the update installation is finished, the installation program restarts the services. This causes an interruption for users, because the users cannot connect to the server during this time.

Small Business Server

You can install Exchange Server 5.5 service packs on an Exchange Server 5.5 computer that is running on Small Business Server without additional special arrangements. When you install a service pack on an Exchange Server 5.5 computer that is running on Small Business Server, just run the service pack or the hotfix. This temporarily stops the Exchange services, and you do not have to restart the computer.

Additional reading

Service pack release notes

To obtain the service pack release note updates, visit the following Microsoft Web site: For more information about how to apply Exchange service packs and hotfixes, click the following article numbers to view the articles in the Microsoft Knowledge Base: For more information about how to obtain the latest Exchange Server 2003 service pack, click the following article numbers to view the articles in the Microsoft Knowledge Base: For more information about how to obtain the latest Exchange 2000 Server service pack, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain the latest Exchange 5.5 Server service pack, click the following article number to view the article in the Microsoft Knowledge Base: