How to deploy an Exchange Server cumulative update
Cumulative updates give the Exchange Server platform stability and security. This guide explains how to perform this maintenance properly to avoid a major service disruption.
When you need to play catch-up with your email system, getting the latest Exchange Server cumulative update is one way to stay compliant and introduce new features to your organization.
Microsoft releases cumulative updates for supported versions of Exchange Server to address security vulnerabilities, correct problems and add new capabilities to the on-premises email platform. Admins should deploy these cumulative updates as soon as possible while following best practices to avoid a lengthy outage. Microsoft typically requires Exchange Server to be on a specific cumulative update to maintain technical support. This guide helps administrators prepare to install an Exchange cumulative update, perform troubleshooting if problems happen and how to undo the upgrade as a last resort.
What are Exchange cumulative updates?
An Exchange cumulative update is a full build of Exchange Server that encompasses every upgrade from the previous cumulative update and any available hotfixes and security updates. In addition to eliminating vulnerabilities, an Exchange Server cumulative update can add stability, improve performance and add new features.
Microsoft originally released Exchange cumulative updates quarterly but gradually changed to a less predictable schedule. Since 2022, the company released one cumulative update a year for Exchange 2019 and one cumulative update total for Exchange Server 2016.
Conduct checks before updating Exchange Server
Before installing an Exchange cumulative update, use the following guidelines to avoid unpleasant surprises during the update.
Review the Microsoft release notes for the cumulative update. This helps you prepare for the prerequisites, known issues or specific instructions that will streamline the update process.
If you have a change management process, consider using it for Exchange Server updates to reduce risks. Backups of your Exchange environment, including its databases, with documented recovery steps to revert to the previous state are helpful if you encounter serious issues. It's also important to have the same backup and restore procedure in place for Active Directory.
During the cumulative update installation, mail flow stops, so plan for service disruption and schedule the update during a period that will affect the fewest users.
Check prerequisites, including service pack and pre-update requirements, sufficient permissions and disk space. Verify if your Exchange Server version meets the prerequisites for the cumulative update. For example, to check the Exchange Server version, use the following PowerShell command:
Get-ExchangeServer | Select Name, AdminDisplayVersion
A PowerShell script that gathers other key information on the Exchange Server, such as .NET Framework version, permissions and perquisites, and outputs the results in the report. This is one way to avoid problems before and after installing the update.
Any Exchange customizations are overwritten so document, review and make backups of these settings. Third-party applications or add-ons may not be compatible with the cumulative update version so plan to address potential conflicts and remedies for this upgrade.
Check the cumulative update on a lab system that mirrors your production setup. This helps you identify and address issues before applying the update in the working Exchange environment.
Ensure you have access to appropriate support channels, whether Microsoft support or internal IT experts, in case of problems during or after the update.
How to deploy the Exchange Server cumulative update
You can use the setup wizard or the Exchange Management Shell to install Exchange cumulative updates. The choice often depends on personal preference or specific requirements.
The setup wizard is a GUI interface that guides administrators step-by-step through the update process, for those less experienced with PowerShell or who prefer a more straightforward method to install updates.
Advanced users or administrators who are comfortable with PowerShell and want more control over the process might prefer the Exchange Management Shell for its automation capabilities. PowerShell simplifies Exchange management by making the execution of tasks repeatable, leading to fewer errors from manual input.
How to install the cumulative update with the setup wizard
To start the installation process using the setup wizard, download the cumulative update from the Microsoft Download Center and save it to a location accessible from the Exchange Server.
Launch the setup process by double-clicking on the cumulative update file. If a User Account Control prompt appears, allow the application to make system changes by entering the necessary credentials.
After reading and accepting the license agreement terms, click Next. If the wizard prompts you to check for updates, choose whether to connect to Microsoft Update or proceed without updates. Click Next.
The setup wizard runs readiness checks to ensure the system meets the update's requirements. Be sure to address any reported issues or warnings before continuing.
Choose the installation type, usually Install only the languages from the DVD or similar options. Select the desired installation location if applicable. Click Install or Next to start the installation.
The setup wizard shows the installation progress. Do not interrupt the operation until it is done.
How to install cumulative updates with the Exchange Management Shell
To start, get the cumulative update from the Microsoft Download Center and place it in a directory accessible from the Exchange Server.
Open the Exchange Management Shell with administrative privileges.
Use the cd command to change to the directory with the cumulative update file. For example:
cd C:\Path\To\CumulativeUpdateFolder
Use the setup.exe or setup.exe /mode:upgrade command with appropriate parameters to start the update process. You might need to provide additional parameters based on your environment and requirements. For example, the following starts the upgrade process and accepts the license terms:
.\Setup.exe /mode:upgrade /IAcceptExchangeServerLicenseTerms
Once the update starts, check for prompts for any actions you might need to perform, such as stopping services, applying changes or restarting services.
Monitor the update progress. It might take some time for the installation process to complete, depending on your server configuration and the update size.
Verify Exchange Server functionality after update
After the installation, check that the update was successful and that Exchange Server services and features are running as expected.
Check that the Exchange Server version corresponds to the cumulative update by using the following PowerShell command to retrieve the version information:
Get-ExchangeServer | Select Name, AdminDisplayVersion
Verify the status of Exchange Servers services to ensure they are running by using PowerShell:
Get-Service *Exchange*
Check that critical services including Microsoft Exchange Information Store, which handles mailbox databases, and Microsoft Exchange Transport, which controls email delivery and routing, are running without errors.
Test client connectivity to Exchange by verifying users can access their mailboxes via the Outlook desktop client, Outlook on the web (OWA), mobile devices and any other client applications. Test sending and receiving emails internally and externally to ensure mail flow works properly.
Check the status of Exchange databases to ensure they are mounted and healthy with this PowerShell command:
Get-MailboxDatabase | Select Name, Mounted
The command returns True or False depending on the mount status of each database.
Microsoft provides a health checker PowerShell script that runs a comprehensive diagnostic test in your Exchange environment to uncover any misconfigurations and problems with other infrastructure, such as load balancers. The script gives the option to output the results in an HTML file and uses color coding to highlight issues in yellow or red to make it easier to debug the system.
Monitor Exchange Server performance and review event logs for any errors or warnings that might indicate issues related to the update. Look for specific Exchange-related events and errors.
How to troubleshoot Exchange Server cumulative update problems
Issues are always possible after updating a working system. If Exchange Server is not performing properly after a cumulative update, diagnosing the issue requires a systematic identification and resolution approach.
Microsoft lists possible issues that might occur after a cumulative update to Exchange Server with the steps to remedy them.
Review installation logs to look for specific error codes or messages. Review the event log for any Exchange-related errors or warnings after you applied the update.
Refer to Microsoft's documentation, release notes and knowledge base articles for the cumulative update. There might be known issues or workarounds to assist in troubleshooting. Microsoft's Tech Community Exchange forum is one place to check if other administrators have reported trouble after installing the cumulative update.
Try to isolate the problem by identifying whether it involves specific services, components, databases or functionalities of Exchange. If the issue persists after troubleshooting, consider contacting Microsoft support for assistance.
How to roll back a cumulative update if troubleshooting fails
When you roll back an Exchange cumulative update, it reverts Exchange Server to its state before the installation process. This requires an experienced Exchange Server admin and should follow proper documentation. Be sure to have tested backup and restore procedures before performing a rollback to minimize the risk of data loss or service disruption.
To roll back Exchange:
- Plan for a maintenance window and inform your users.
- Stop Exchange Server services via the services console or the Exchange Management Shell.
- Restore the Exchange Server with the backup using the appropriate tools.
- If the Exchange databases were upgraded as part of the cumulative update installation, consider replaying the database logs to bring the databases back to the state before the update.
- After the restore process, do another round of verification checks to make sure Exchange Server went back to the version before the cumulative update installation.
- Restart the Exchange services and perform any necessary configurations or adjustments to ensure the server operates and functions correctly.
Helen Searle-Jones holds a group head of IT position in the manufacturing sector. She draws on 30 years of experience in enterprise and end-user computing, utilizing cloud and on-premises technologies to enhance IT performance.
