https://medium.com/@AnupamMajhi/windows-deleting-orphaned-dfs-share-63c0a3201a70
WINDOWS: Deleting Orphaned DFS Share
Error message saying the share must be removed from the distributed file system before it can be deleted.
Either
Find the registry entry for that DFS and delete the key named with the DFS name under:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DFSRoots\Domain
OR
Run the command:
dfsutil /clean /server: /share:
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The next step is to go to services and restart the service called "Server".
"DFS Namespaces" service is dependent on it, so go ahead and accept the prompt that says this will restart "DFS Namespaces".
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Now go back to the share and remove it without any problems.