How do I disable the Outlook auto-complete and clear the cache

If you are experiencing a lot of failed sent mail due to malformed addresses in your auto-complete or address book follow these instructions on how to clear your list and cache.
  • In Outlook 2010 and 2013, click the File menu and select Options.
  • In the Outlook Options window click the Mail tab.
  • Scroll down to Send messages. Uncheck the Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines box.
  • Optional Step: To clear out the auto-complete list, simply click the Empty Auto-Complete List button.
  • You’ll see a confirmation window about clearing the auto-complete list, click Yes.
  • Outlook auto-complete should be completely disabled and any history that was in the auto-complete list should be completely erased (if you clicked the clear auto-complete button).
    More information about fixing nickname and autocomplete lists can be found on Microsoft's support site.
    Creation date: 9/20/2017 9:29 AM      Updated: 9/20/2017 9:29 AM