Where did my auto complete email addresses go? 

When you start a new email and start typing a recipients name you are normally prompted to complete the address by Outlook. In 2007 and earlier versions this information was stored in a file on the C drive (Docs and Settingsuser nameapplicationsMicrosoftOutlook) which had a file extension NK2. Since the introduction of Office / Outlook 2010 this file no longer gets created and instead these contacts are stored within the PST file, just look for ‘Suggested Contacts’. So if you ever happen to create a new Outlook profile just locate your old PST file and extract the suggested contacts.