You can unregister an external index collection from your system. Doing this severs the connection between your system and the external index and deletes the index collection, but does not delete the index itself. You can continue to search the index (not through your system) or, in the case of an external Solr index, update and manage the index.
You cannot unregister an internal index collection, but you can delete them. For information, see Deleting an index collection.
You cannot unregister an index collection that's part of a workflow that has a running task.
To unregister an index collection:
Click the Index Collections window.
Click the remove icon () for the index collection you want unregister.