Updating Exchange 2019 CU on Windows 2019 Core Server.

3 min readOct 26, 2018

In this blog, I will review the Exchange 2019 updating process on Windows 2019 Core edition.
The updating process is actually installing a new cumulative update (CU) on the current version, similar to the “In Place” upgrade.
Unlike the previous Exchange’s versions, Exchange 2019 is not available for download free from Microsoft website, it is only available from VLSC (Volume License Service Center) or from MSDN for testing and development purposes.

Before running the update process:

Be aware that there changes between the different Exchange’s CUs, meaning that third-party software or any system that collaborates might stop working at the worst case.
Therefore, it is highly recommended to act as the following:

install the CU on a lab/test environment, verify that everything is working and then install it on the production environment.
Check with all third-party application’s vendors, that their application is supported with the Exchange’s CU version that is going to install.
Review the CU release notes, to verify that your servers are having all the prerequisites (for an example .Net version) for the CU installation.
Enter the planed updated server into a maintenance mode: https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/manage-dags?view=exchserver-2019#performing-maintenance-on-dag-members

Running Exchange 2019 update process:

After completing the tasks above, you can safely update your Exchange server.
Since you cannot download the ISO file from the Windows Core server, you should download the ISO file from another machine and then copy it to the Exchange server.

After copying the ISO to the Exchange server, we have to mount it, in order to access the setup file and run the installation.
To mount the ISO, run the following command, with the path where the ISO is located:

Mount-DiskImage C:\Setup\E19\mu_exchange_server_2019_cumulative_update_1_x64_dvd_6c695b62.iso

To get the list of all drive letters and the location of the mounted ISO, you can run the following command:

Get-volume

After completing mounting the ISO, close the PowerShell window and go back to the CMD window.

It is also recommended to close/stop any Antivirus software before running the update process.

Now navigate to the mounted drive where the installation is located (Drive E: in our example) and run the following command:

Setup.exe /m:upgrade /IacceptExchangeServerLicenseTerms

In case that there is a process (12820 in this case) that interrupts the updating process, you can stop it using the next command from a PowerShell window after the installation stopped: