sluge,

вот один из советов
авторAutocompletion is not a robust or reliable feature. It frequently stops working usually because Outlook loses its connection to its autocompletion cache. This can happen for a number of reasons, most often because Outlook is not exiting completely and thus not writing to the cache. Make sure you run no add-ins or sync software that might hold Outlook open after you exit. After you find and resolve the problem that is preventing Outlook from exiting properly, you may need to create a new Outlook profile to get autocompletion to work again.
остальные - здесь .