Remove Outlook Auto Complete Cache

May 11 2016
POSTED IN Tips and Tricks

Did you know that Microsoft Outlook has 3 main ways to find contacts when addressing an email to someone?

Here are the different ways to find contacts:

  1. The Global Address List (GAL) is a directory maintained by your IT department and it tends to have all organizational users, distribution lists, and excludes some hidden files.

  2. Your Contact lists include any contacts that you have cultivated and stored inside outlook.

  3. Auto-Complete cache, which used to be simply called the Nickname or N2K file.

The Auto-Complete Cache works by remembering people you’ve emailed before and creating internal fast shortcuts to those people. In older versions of Outlook, the N2K file was stored on your hard drive, but in Outlook 2010 onwards it has been incorporated directly into the files that Outlook stores on your exchange server. Sometimes, however, the Auto-Complete can get you in trouble.

How does it cause problems?

Since it remembers the last used email, if one of your recipients changes their email address, Outlook may try to send email to the wrong location. This can happen even if you have updated your contact list. This is the same for internal changes; people who change their names or move departments in your organization can create the same problem – this can be annoying at times!  To facilitate this, IT may have to make changes in the GAL. Sometimes when these changes are made, the Auto-Complete Cache doesn’t update as it should.


When these background changes happen and Auto-Complete has an issue with them, you will start seeing issues with particular recipients where:

  • the email always bounces with a message that the user doesn’t exist
  • the email does not want to send
  • or you keep sending to the wrong email address.

How do you solve this?

Your best bet is to clear the cached email addresses for the recipient that seems to be having the issue.

For individual email addresses the process is:

  1. Inside Outlook, Type the email address you wish to clear from the cache until Outlook displays it as shown above.
  2. Press the down arrow key to select the email address and press the delete button.
  3. All done! That entry should now be gone from the Outlook Auto-Complete cache.




Recently, I’ve had  issues with users who have emailed me multiple times from several different email addresses. It was becoming overwhelming to have to deal with them all.. Ultimately, I decided that erasing my entire Auto-Complete cache was less painful than dealing individually with the cruft.


Here’s how you do it, too!  

  1. In Outlook, Click the File menu and Select Options.

  2. In the Outlook Options window, Click the Mail tab.

  3. To clear out the Auto-Complete list, simply Click the Empty Auto-Complete List button.

  4. You’ll see a confirmation window about clearing the Auto-Complete list, Click Yes.


Interested in learning more about how our IT department can help your company?

Call Mantralogix at 1-866-320-8922 or email us at [email protected] and we’d be happy to help! In fact, we’ve been specializing in ERP/Accounting and CRM solutions, as well as a host of leading IT solutions & services, for over 20 years!

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