Tag Archives: exchange server

This computer is a member of a database availability group (DAG)

When uninstalling an Exchange server that is part of a Database Availability Group, you perform several steps to remove the server from the DAG and maybe even delete the DAG itself.

So, after decommissioning the DAG I wanted to uninstall Exchange, but the readiness check failed with the following error message:

This computer is a member of a database availability group (DAG). It must be removed from the DAG before you can uninstall Exchange. For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.CannotUninstallClusterNode.aspx

Unfortunately this link has not been updates since 2015, and does not contain any useful information.

I decommissioned the DAG earlier as you can see in the following screenshot, but it still failed the readiness check:

When using the Get-DatabaseAvailabilityGroup command nothing showed up, and also when checking Active Directory with ADSI Edit (CN=Organization, CN=Administrative Groups, CN=Exchange Administrative Group (FYDIBOHF23SPDLT), CN=Database Availability Groups) nothing is shown.

The DAG is using bits of Windows failover clustering, so the culprit must be there. When executing the Get-ClusterNode and Get-Cluster commands in PowerShell, some DAG leftovers (on this particular machine) showed up:

Something must have gone wrong during decommissioning of the DAG, although no error were shown on the console.

To remove the cluster node (and thus the cluster) from this machine, execute the following command in PowerShell:

PS C:\> Remove-ClusterNode EXCH12 -Force

After this step uninstalling Exchange succeeds.

Office 365 Directory Synchronization without Exchange server Part II

The question in my previous blog post was “Can we decommission our Exchange servers after moving to Office 365?” and the blunt answer was “No, you cannot decommission your last Exchange server on-premises”.

In this previous blog post I showed you what happens if you synchronize a user to Azure Active Directory from your on-premises Active Directory, and how to create a Mailbox in Exchange Online with a proper primary Email address. At the same time, it was only possible to set only one Email address, and there’s no possibility to add multiple Email addresses, nor is it possible to change any other Exchange related setting.

In this blog post I’ll discuss how to extend Active Directory with Exchange attributes to unleash more functionality and management options in Exchange Online. Please note that the solution in this blog works fine, but it is not recommended and not supported by Microsoft. Continue reading Office 365 Directory Synchronization without Exchange server Part II

How to brand OWA in Exchange 2013

This page is updated with information on Exchange 2016 and Exchange 2019.

A long time ago, Jeff Guillet wrote an excellent post on his EXPTA {blog} on how to brand the OWA logon page in Exchange 2007 and Exchange 2010, which is perfect when testing load balancing solutions. You can find this post here: http://www.expta.com/2010/03/how-to-brand-owa-2007-and-2010-with.html.

For testing OWA in Exchange 2013 and higher, the process is somewhat similar. On the Exchange 2013 Client Access server or Exchange 2016/2019 Mailbox Server, navigate to the C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa\auth directory and open the logon.aspx page with (for example) Notepad. If you are running Exchange 2019 on Windows Server Core you can use the following command:

Notepad “C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa\auth\logon.aspx”

In this file, scroll down to the div class=”logonContainer” section and add the servername text just before the UserNameLabel variable, as shown in the following screenshot (click to enlarge)

OWA Logon.aspx

Save the file and in your browser navigate to the Exchange Server to see the results:

owa branding

Warning. When upgrading to a new CU, the logon.aspx is overwritten and you have to make these changes again.

And another warning…. I’m not so sure if this is fully supported by Microsoft 😊

Last Updated on February 27, 2019