If you want to delete an address from the autocomplete list in Outlook, follow these steps:

1. Create a new email and start typing the address:
   
   
   
   
    
2. Use the down arrow to highlight the address you want to delete:
   
   
   
   
    
3. Press the delete key.  If this doesn't work, continue below.

 

 

If for some reason the above doesn't work, this is another way to do the same.

1. Click File:
   
   
   
   
    
2. Click Options:
   
   
   
   
    
3. Click Mail:
   
   
   
   
    
4. Scroll down to Send messages, then click the Empty Auto-complete List button:
   NOTE: this will empty the full auto-complete list but not your address book