Nir Sofer - ( Freeware)
NK2Edit is a handy utility for editing the .NK2 files generated by Outlook as desired.
NK2Edit is a simple and lightweight utility developed to edit the .NK2 files generated by Outlook, being an editor for Microsoft Outlook that can add, remove, edit or fix corrupt auto complete records in the email package. The application will record all entries to the email addresses you suggest through an autocompleting system when enter the first letters of the address and therefore will allow to edit this file to correct the data, or better, add new, delete unnecessary ones, merge several records together to avoid redundancy, fix corrupted and more. NK2Edit also creates a new file with .NK2 containing only the addresses you have given him. Finally, the utility offers the ability to export data in the .NK2 file in an HTML, text, CSV, XML or just in the Outlook address book.
Added 'Quick Filter' feature (View -> Use Quick Filter or Ctrl+Q). When it's turned on, you can type a string in the text-box added under the toolbar and NK2Edit will instantly filter the AutoComplete items, showing only items that contain the string you typed.