Outlook 2013 or Outlook 2010
- Click File, and then click Options.
- Select the Mail tab.
- Scroll approximately halfway down until you see Send messages. Make sure that the Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines box is checked. The screen shot for this step is listed below).
- Click Tools, and then click Options.
- Click the E-mail options button.
- Click the Advanced E-mail Options button.
- Make sure that the Suggest names while completing To, Cc, and Bcc fields box is checked. (The screen shot for this step is listed below).
If the Auto-Complete feature is enabled and you are experiencing the behavior that is mentioned in the "Symptoms" section, the Auto-Complete cache may be damaged. The Auto-Complete cache cannot be repaired. It must be deleted.
For more information about clearing the Auto-Complete cache, click the following article number to view the article in the Microsoft Knowledge Base:
Article ID: 2802193 - Last Review: Dec 31, 2014 - Revision: 1