In this quick guide I will show you how to completely remove a Skype for Business 2015 deployment. (This also works for Lync Server 2013).
First Step (Disable all users)
Run the following command to disable all users in the SfB pool:
Get-CsUser | Disable-CsUser
Second Step (Remove Conference Directories)
Run the following command to remove all conferences that have been configured in the pool:
Get-CSConferencingDirectory
You can run the following command to delete them:
Double check by running the Get-CSConferencingDirectory command again. If there are any remaining then use the following command to remove them individually:
Third Step (Remove additional components)
Run the following commands:
Get-CsTrustedApplication | Remove-CsTrustedApplication –force
Get-CsCallParkOrbit
Now delete all gateways in the Topiology Builder.
Once deleted publish the topology.
Forth Step (Remove Edge Server)
Remove the Edge Server and its associations with Front End Pool in the Topology Builder.
Publish Topology then Export Configuration from the Front-End server using
Edge server can now be physically turned off or deleted if its a virtual machine.
Fifth Step (Remove the remainder of the topology)
Open the Topology Builder and download the topology.
Click Actions > Remove Deployment and run through the wizard.
Publish the Topology.
Open the SfB Management Shell and type:
Keep running the command until all your Front End Servers are UpToDate: True
Now run:
Ensure the update is in the last few minutes.
Now run:
Publish-CsTopology –FinalizeUninstall
Now the Topology has been destroyed run the bootstrapper with the /scorch switch. You need to run the bootstrapper /scorch command because replication has stopped. The command removes the final references and files from the decommissioned Front End Server.
Run the bootstrapper (or topology builder if you wish) on the remaining SfB Servers.
Nearly There (Remove the Databases & AD References)
See this link for a list of the databases: https://insidemstech.com/tag/skype-for-business-databases/
Run these last few commands to remove any reference: