Various blogs suggest to delete entirely the search service and start afresh. This a fairly drastic approach and not always practical with a production environment. Our fix was to create a new crawl component on the same server within Central Administration, this took 10 minutes to process but when it came back both the new and existing crawl components where online.
Crawl component stuck on ‘Recovering’
Two crawl components on same server.
Delete the new crawl component.
