Anteaus wrote:

Thanks for reply. There appear to be some third-party apps that can
convert this .nk2 file into contacts, but what we need is the
reverse.

Easy to do. Open your Contacts folder and select all the entries in it with
CTRl-A. Click ActionsNew Message to Contact to get a compose window with
all your contacts in the To field. Press CTRL-K to resolve all the
addresses. This will add them to the NK2 file. Close the compose window
without sending the message.
--
Brian Tillman [MVP-Outlook]