How to clear the Outlook auto-complete cache


The auto-complete cache is comprised of previously used email addresses and is useful for quickly addressing new messages.  The cache can get stale or it may contain entries you no longer need.  There are a few ways to clear the cache.

Step-by-step guide

Clearing the cache, one entry at a time

  1. Begin typing a person’s name and when the cached entry comes up, click the X on the right-side of the entry, as shown below.


    This will remove that entry from the auto-complete cache.  The next time you address a message to that person, their most current email address and display name will be added back to the cache. 

Clearing the entire auto-complete cache

If you have a lot of stale entries in the cache, you can clear them all at once using two different methods.

Method 1:

You can clear Outlooks auto-complete cache with a simple command. 

  1. Close Outlook then click the Start button .
  2. In the Search programs and files field type (or copy and paste): C:\Program Files (x86)\Microsoft Office\office15\outlook.exe /cleanautocompletechache, as shown below and press Enter.  This will open Outlook and simultaneously clear the cache.



Method 2:

In Outlook, go to File → Options → Mail.  Scroll to the Send Messages section and click Empty Auto-Complete List to clear every entry in the list.  The cache will start rebuilding itself as you send out new messages.