Delete old email addresses from Outlook
How to delete or remove old email addresses in Outlook from cache?
Most of the times users face issues with old email addresses saved in the outlook cache when sending email to an old client. If the old client`s company has changed their domain from abc.com to xyz.com then the user who is sending the email to old email address (which is stored in memory of the outlook) will get a bounce back.
This is an all too common experience for many users.
Solution:
If you are using Outlook 2002/2003/2007, use the arrow key to select the incorrect address and press the Delete key. You can also clear the entire nickname file (*.NK2) by deleting it.
Older versions of Outlook store nicknames in a file using the extension *.nick but do not support using it for auto complete.
The nickname files are found at C:\Documents and Settings\username\Application Data\Microsoft\Outlook if you are using Windows XP/2000 or C:\Users\username\Application Data\Microsoft\Outlook. You can easily access it by pasting %USERPROFILE%\Application Data\Microsoft\Outlook in the Address bar of your browser or Windows Explorer.