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Install Cumulative Update Exchange 2016

You have to install a Cumulative Update in Exchange 2016. It’s good to keep the Exchange Server up to date. Plan the update before starting and have in mind that it can take time before it finishes. If you have only one Exchange Server, mail flow will not work at that time. Now, what is the best procedure to install Cumulative Update in Exchange 2016?

There are two options to upgrade Exchange Server 2016. Update Exchange with Graphic User Interface (GUI) or unattended mode (command line). The organization that I want to install the Cumulative Update for does have two Exchange Servers. I am going to install the Cumulative Update on the Exchange Server EX01. The other Exchange Server is named EX02. In this article, you will learn how to use unattended mode to install Cumulative Update in Exchange 2016.

Good to know before installing Cumulative Update

  • After you upgrade Exchange to a newer CU, you can’t uninstall the new version to revert to the previous version. Uninstalling the new version completely removes Exchange from the server.
  • Any customized Exchange or Internet Information Server (IIS) settings that you made in Exchange XML application configuration files on the Exchange server (for example, web.config files or the EdgeTransport.exe.config file) will be overwritten when you install an Exchange CU. Be sure to save this information so you can easily re-apply the settings after the install.

Install Cumulative Updates best practices

Before the Cumulative Update:

  • Check for Windows Updates and install the updates
  • Restart the server
  • Put the server in maintenance mode
  • Temporarily disable any anti-virus software
  • Temporarily disable any back-up software
  • Place the server in maintenance mode in the monitoring systems, for example SCOM
  • Use an elevated command prompt to run the Cumulative Update

After the Cumulative Update:

  • Restart the server
  • Check the event logs by filtering for errors and warnings
  • Take the server out of maintenance mode
  • Enable back-up software
  • Enable anti-virus
  • Take the server out of maintenance mode in the monitoring systems, for example SCOM

Put Exchange Server in maintenance mode

Read more in the article Put Exchange Server in maintenance mode.

Login on the Exchange Server EX01. Run Exchange Management Shell as administrator. Set the Hub Transport Service to draining. It will stop accepting any more messages.

Redirect any queued messages to EX02. The target Server value has to be the target server’s FQDN. The target server shouldn’t be in maintenance mode.

If the server is a DAG member, run the following commands. If your server is not a DAG member, skip to the command for setting ServerWideOffline.

Pause the cluster node. Suspend Server EX01 from the DAG.

Disable database copy automatic activation. This command will also move any active database copies to other DAG members. Assuming there are other healthy DAG members available. This is not instantaneous, it can take several minutes for the moves to occur. We’ll check it in one of the following commands.

Make a note of the database copy automatic activation policy on the server. You can set it back to this value at the end of maintenance. The default setting is Unrestricted.

Set it to Blocked to prevent any of the databases from becoming Active.

Check for any database copies that are still mounted on the server. It may take a while for the Active databases to move. This command should return no results. If any database copies are still active on the server, and there are other DAG members that host copies of the database, perform a manual switchover.

Once the active databases have been moved, we will check the transport queue. Queues should be empty or almost empty, as we will be disabling all server components. Any emails still pending in the queues will have a delay in delivery till the server is  taken out from maintenance mode.

Put the Server EX01 into maintenance mode.

Check the load balancer

Do you have the Exchange Server configured in a load balancer? Verify that the load balancer health checks have taken the server out of the pool or marked it as offline/inactive. If the load balancer does not automatically do this, manually mark the server as offline/inactive. Log into your load balancer and set any virtual services you have to disable any connections to Server EX01. Typically there would be SMTP and HTTPS virtual services. This will force any future connections to Server EX01.

How to verify Exchange Server is in maintenance mode

Verify if the Exchange Server EX01 has been placed into maintenance mode. All components should show Inactive except for Monitoring and RecoveryActionsEnabled.

Which .NET Framework and Exchange Server Cumulative Update

Read more in the article Update .NET Framework in Exchange Server 2016.

A lot of Exchange admins have seen Exchange Servers breaking and not working after a Cumulative Update. It’s important to know that .NET Framework is a must for Exchange Server. When installing Cumulative Updates on Exchange 2016, we sometimes have to update .NET Framework. That is not always the case. Sometimes you can run the Cumulative Update without updating .NET Framework. Yes, we can download .NET Framework for free.

What Microsoft is saying about .NET Framework:

When upgrading Exchange Server from an unsupported CU to the current CU and no intermediate CUs are available, you should first upgrade to the latest version of .NET that’s supported by your version of Exchange Server and then immediately upgrade to the current CU. This method doesn’t replace the need to keep your Exchange servers up to date and on the latest supported CU. Microsoft makes no claim that an upgrade failure will not occur using this method, which may result in the need to contact Microsoft Support Services.

Keep .NET Framework and Exchange Server 2016 up to date

Keep your Exchange Server 2016 up to date so that you don’t have to carry out a longer update path. I recommend downloading the Exchange CU ISO when it’s available and save it to the hard disk. Microsoft does remove older Exchange CUs when newer versions are released. When saving the Exchange CU ISO, you can always carry out the upgrade path. You can use an unofficial website to download an older Exchange CU.

How to update .NET Framework and Exchange Server Cumulative Update

Don’t immediately update when a .NET Framework version or Exchange Server version is released. Always wait and check if bugs are raising. Don’t forget to always test the Exchange Server CU in a test environment before updating it in production.

I made a flowchart that will show the procedure on how to update .NET Framework and Exchange Server Cumulative Update.

Install Cumulative Update Exchange 2016 flowchart

To keep it simple, keep these two steps in mind when planning the update path:

  1. Update to the last Exchange version that is supported by the .NET Framework (blue arrow)
  2. Update to the last .NET Framework that is supported for the Exchange Server (green arrow)

Keep updating till you’re on the version that you want to be. It will most likely be the last released Exchange version. Use the given flowchart. It’s easy to follow the update path for Exchange Server Cumulative Update and .NET Framework.

Install .NET Framework

We are going to update from Exchange Server 2016 CU14 to Exchange Server 2016 CU16. Go to the download page of .NET Framework and download the appropriate version. In our case, it will be .NET Framework 4.8. If the download is finished, right-click the file and choose run as administrator. Install the .NET Framework on the Exchange Server. Restart when the installation is completed.

Prepare Active Directory and Domains

Read more in the article Prepare Active Directory and domains for Exchange Server.

Download Exchange Cumulative Update

Before we can prepare AD for Exchange 2016, we need to download the Exchange 2016 CU ISO. Go to the following page to get a list of the Exchange Server CU. The page will show you the Exchange Server build numbers and release dates. Scroll down for Exchange Server 2016. Download the Exchange Server 2016 Cumulative Update and place it in the C:\install folder. Create an install folder if you don’t have one.

In File Explorer, right-click on the Exchange Server 2016 CU16 ISO image file and select Mount. It will mount the ISO image to a drive. For example, the E:\ drive. The E:\ drive contains the Exchange installation files. Make sure to mount the Exchange ISO image before proceeding to the next step.

Install Cumulative Update Exchange 2016 mount ISO

Before extending the Active Directory schema, the following needs to be installed on the Exchange Server:

  • The RSAT-ADDS feature must be installed
  • Account needs to be added to the Schema Admins and Enterprise Admins security groups
You can extend the Active Directory Schema from the domain controller or any other server in the organization. The feature RSAT-ADDS is already installed on the domain controller. If you want to prepare the schema on the Domain Controller, you only need to install the .NET framework. Some organizations have different teams because of different administrative responsibilities in the environment.

Install RSAT-ADDS feature

RSAT-ADDS feature is already installed on the domain controller and Exchange Server. Install the RSAT-ADDS feature. Run PowerShell as administrator. Run the Install-WindowsFeature cmdlet including the RSAT-ADDS feature. If you are not sure if it’s installed on the system, run the command and it will tell you if there are no changes needed.

Schema Admins and Enterprise Admins security groups

Before you can extend the schema, your account needs to be a member of the Schema Admins and Enterprise Admins security groups. Open Active Directory and add both groups to your account if it’s not set already. These are high privilege groups. I recommend you to remove your account from the groups when you’re done with this task. Note, if you’ve just added yourself to these groups you’ll need to log out and back into the server for the new group membership to take effect.

Install Cumulative Update Exchange 2016 security groups

Prepare Active Directory Schema

The first step in getting your organization ready for Exchange 2016 is to extend the Active Directory schema. Exchange stores a lot of information in Active Directory but before it can do that, it needs to add/update classes and attributes.

Run Command Prompt as administrator. Run the following command to extend/prepare the schema for Exchange 2016.

You will see the COMPLETED messages in the output. The extend/prepare schema for Exchange 2016 went successfully.

Prepare Active Directory

After the Active Directory schema has been extended, you can prepare other parts of Active Directory for Exchange 2016. During this step, Exchange will create containers, objects, and other items in Active Directory to store information. The collection of the Exchange containers, objects, attributes, and so on, is called the Exchange organization.

Run Command Prompt as administrator. Run the following command to prepare Active Directory for Exchange 2016.

Prepare Active Directory domains

The final step to get Active Directory ready for Exchange is to prepare each of the Active Directory domains where Exchange will be installed. This step creates additional containers, security groups, and sets permissions so that Exchange can access them.

If you have more than one domain, you can run the following command to prepare all the domains for Exchange 2016.

If you have only one domain, you can skip this step because the /PrepareAD command in the previous step has already prepared the domain for you.

Check Exchange Active Directory versions

After you did prepare the AD for Exchange 2016, you like to check if the Active Directory is updated. Run PowerShell as administrator. Make sure that you set the Execution Policy to Unrestricted. Press Y and Enter. If you don’t, the script will not run.

Download the script Get-ADversions.ps1 and run it. For more information, read the article check Exchange Schema version with PowerShell. You can also run the following commands one by one.

How to confirm the Exchange Active Directory versions? Visit the Microsoft Docs page and scroll to the bottom of the page to find the Active Directory versions. The list is being kept up to date by Microsoft.

Install Cumulative Update Exchange 2016 schema versions

Install Cumulative Update Exchange 2016 unattended mode

Run Command Prompt as administrator. Run the command to start the Cumulative Update for Exchange 2016.

The update did go successfully. Restart the Exchange Server.

Testing

Check the event logs by filtering for errors and warnings. If there are errors, make sure to troubleshoot and fix them.

Take Exchange Server out of maintenance mode

Read more in the article Take Exchange Server out of maintenance mode.

After the update, we like to get the Exchange Server EX01 to be active again. Run Exchange Management Shell as administrator.

You can now remove the server from maintenance mode. Note: If the server is not a DAG member, only the first and last commands are necessary. If the server is a DAG member, you need to run all the commands. Use the database copy auto-activation policy value that was set on the server. The default is Unrestricted.

Rebalance Database Availability Groups

Throughout the update process, the database copies will move between DAG members. Return your active database copies to their most preferred DAG member. Use the PowerShell script supplied by Microsoft.

Verify out of maintenance mode

Verify if the Exchange Server EX01 is back up and running. Run the following commands.

The cluster node needs to have the state up.

Check that the cluster node has the state up on all the Exchange Servers.

Check that all the required services are running.

Test the MAPI Connectivity.

Test the MAPI Connectivity on all the Exchange Servers.

Get the result of the DAG Copy Status Health.

Get the result of the DAG Copy Status Health on all the Exchange Servers.

Check the Replication Health.

Check the Replication Health on all the Exchange Servers.

Verify the Database Activation Policy is set to Unrestricted.

Verify the Database Activation Policy is set to Unrestricted on all the Exchange Servers.

Load balancer

Do you have the Exchange Server configured in a load balancer? Verify that the load balancer health checks have taken the server in the pool or marked it as online/active. If the load balancer does not automatically do this, manually mark the server as online/active. Log into your load balancer and set any virtual services you have to enable any connections to Server EX01. Typically there would be SMTP and HTTPS virtual services. This will enable connections to Server EX01.

Conclusion

In this article, you learned how to install Cumulative Update Exchange in 2016. It’s important to know that you plan it accordingly by using the flowchart. Download the appropriate CU and .NET Framework setup files. Place the server in maintenance mode and install the update following with a system restart. In this article, we did use the unattended mode to install the Cumulative Update. As last, take the Exchange Server out of maintenance mode.

Did you enjoy this article? If so, you may like the article Create bulk mailboxes in Exchange 2016 with PowerShell. Don’t forget to follow us and share this article.

ALI TAJRAN

ALI TAJRAN

ALI TAJRAN is a passionate IT Architect, IT Consultant, and Microsoft Certified Trainer. He started Information Technology at a very young age, and his goal is to teach and inspire others. Connect with ALI TAJRAN on social media. Read more »

This Post Has 8 Comments

    1. It would be best to keep the differences between CUs as short as possible to prevent unexpected issues. That’s why I recommend doing it on the same day. If you want to install the CU on one Exchange Server first and wait it out for a week, this is supported. But don’t wait too long. Update the remaining Exchange Servers within a couple of days or a week and not after months.

  1. Thank you very much for confirming – much appreciated.

    Excellent article very comprehensive with outstanding attention to detail.

    1. Correct, you have to keep the Exchange Servers builds on the same version. Finish the first Exchange Server with the Cumulative Update. Do the health check and move the mailbox databases to it. Start the process again, this time for the second Exchange Server. If you have more than two Exchange Servers, keep on going, as you have to do all of them.

      Remember to keep this order:
      Update mailbox servers in the internet-facing sites
      Update mailbox servers in remaining internal sites (if any)
      Update Edge Transport servers (if any)

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