Overview
Sometimes you need to delete a DFS Namespace whether it was a test namespace or your DFS structure just changed. This can lead to 'orphaned' namespaces, that still show up in the event logs and the DFS Management console.
How to Completely Remove Orphaned Namespaces
DFS stores these namespaces in the Active Directory database, so while the filesystem part of the DFS has been deleted, the AD entries remain. The solution is to use ADSI Edit.
Using ADSI Edit navigate to the following location:
Default Naming Context\DC=YourDomain,DC=FQDN\CN=System\CN=Dfs-Configuration
From there you should see a list of your namespaces (current and orphaned) that should look something like this:
CN=DATA CN=Orphaned
Now just right click and delete the orphaned namespace.
Close ADSI Edit.
Now open the DFS Management Console and right click the orphaned namespace and click "Remove Namespace from Display".
That should take care of the orphaned namespaces. It will take time for AD Database chanced you just made to propagate to all your Domain Controllers.
You can speed up the replication process by running:
repadmin /syncall
You can also run this commnd on all DFS member servers to force them to sync from the AD Database:
dfsrdiag pollad