After a (successful) migration from Lync 2010 to Lync 2013 I wanted to decommission the old Lync 2010 servers. In my previous blog post I already explained why the CMS didn’t want to move, but the next issue was challenging as well.

Before removing the last Lync front-end server you have to remove all Lync 2010 objects from this front-end server. Well known issue for example is the conference directory that for some reason always stays at the front-end server.

But after removing everything from the old Lync 2010 environment and removing the Lync 2010 front-end server from the Topology using the Topology Builder, it still would not publish:

It generated the following error:

Error: An error occurred: “System.InvalidOperationException” “Cannot publish topology changes. Users or contacts are still homed on a pool that would be deleted. Move or remove the users or contacts before continuing.”

Really everything was empty and all object were removed from the Lync 2010 Topology. Again lots banging my head on the desk… until I realized I had been experimenting with Exchange Unified Messaging, and there are some leftovers in Active Directory for the system attendant. Open the OcsUmUtil tool that can be found in C:\Program Files\Common Files\Microsoft Lync Server 2010\Support, press Load Data et voila, there’s the contact that’s causing the issue:

Click the Delete button to remove the contact and publish your new Lync Topology. Now it will succeed.