A customer running Exchange 2013 Cu2 was facing an issue with their OWA. search did not working and just gave an error. The application and system event log was reporting issue with the hostcontroller.exe. The service «Microsoft Exchange Host Search Controller» was not running and would just terminale unexpectedl when I tried to start it. Deleting the index database didnt help either, still no search results.
the solution was to run the following (see the screenshot). I then deleted the content index database (which remains in a sub-catalogue where you have your mailbox databases) and restartet both «Microsoft Exchange Search» and «Microsoft Exchange Host Search Controller». After a few minutes a few .tmp files was created and deleted fast in the same dir as the mailboxdatabases resides, starting with cts*.tmp. After that the search was working and the search service also run fine.