outlook

Location:

C:\Users\username\AppData\Local\Microsoft\Outlook\RoamCache

Introduction
Every time that you type an email address or name in the message window of MS-Outlook, it automatically offer you a list of users and email address that you can choose. This feature is known as 'AutoComplete' and Outlook automatically build this emails list according to user activity and save it into a file with .NK2 extension.

Outlook AutoComplete