NirSoft NK2Edit

Whenever you start typing an email address or a name in the message window, Outlook magically offers you a list of users and email addresses to choose from. This time-saving gem is known as 'AutoComplete,' Outlook diligently compiles this list based on your usage patterns, storing it in a file with a .NK2 extension. It is a powerful tool that lets you take control of your Outlook AutoComplete data.