After building a brand new Skype for Business environment for a customer, I set about decommissioning their legacy Lync 2013 environment. Everything was going well until I tried to remove the Lync 2013 Director from the topology.
Whilst publishing the updated topology, the wizard spat back the following error:
Error: 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
Alright, where are these pesky users or contacts?
Well, turns out that the user that was causing all the issues had been migrated to Office 365 Lync online prior to the environment being decommissioned. This user still had remnants of the Lync director within its properties, although none of this showed up on prem when running Get-CSUser
To fix this issue, I migrated the user from Lync online, down to a newly built Skype for Business front end pool. Doing so updated the users properties which then allowed me to remove the Lync Director from the topology.