Clear Nickname Cache

Student email accounts were transitioned to the new mail servers recently.  This led to some faculty and staff being unable to send emails to them, with emails bouncing back as undelivered. 

This was caused by the “nickname” cache in Outlook.  If you’ve previously sent an email directly to a student their email address and the “Nickname” or Display Name, associated with it were stored in Outlook.  This is supposed to make sending additional messages easier.  Unfortunately, this saves more than just what is visible to the user.  It also saves behind-the-scenes server information.  When the accounts moved, that server information didn’t update.  This resulted in messages being sent to the wrong “address”. 

Correcting this is simple… 

How to remove nickname cache entries, one at a time 

  1. Open a new email message.
  2. Type the first few characters of the nickname cache entry that you want to remove from the cache.
  3. When the entry appears in the list of suggested names, move your mouse pointer over the name until it becomes highlighted, but do not click the name.
  4. When the “X” icon appears next to the highlighted name, click X to remove the name from the list. 

How to clear the whole nickname cache at once 

  1. Close all Microsoft Office programs
  2. Click the following link and run the small application which download: 

For more information on this issue, please see the following Microsoft Support page:


If you run into any additional issues, please contact the Help Desk for assistance.