When you start to type a name or email address within the To/CC field it trys to complete itself by looking up previous entries.  It does not actually lookup within your current contacts.

As a result you may end up with the autocomplete bring up old email addresses or wrong addresses that you have previously entered.  This information is stored within a file, now wouldn't it be great if you could edit this file from time to time.  To remove invalid entries, remove duplicates or even add new entries.

The AutoComplete file of Outlook is stored under [Your Profile]\Application Data\Microsoft\Outlook , and it always saved as the profile name of Outlook with .NK2 extension.

Thanks to www.nirsoft.net there is now a utility to edit this .NK2 file.  This utility reads the AutoComplete file of Outlook (with .NK2 extension), displays all email records stored in it, and allows you to easily export these records into text/html/xml file.

NK2View doesn't require any installation process or additional DLL files.  Just copy the executable file (nk2view.exe) to any folder you like, and run it.

After your run it, NK2View utility displays the AutoComplete list of the default Outlook profile.  If you want to view the AutoComplete list of other profiles, simply use the 'Open .NK2 File' option.