I have tested this in Outlook 2013 and it worked. The instructions are for Outlook 2010. The Export option below was also successful though more involved.

http://blog.lanlogic.net/kb/hosted-exchange/how-to-copy-the-autocomplete-information-to-a-new-outlook-2003-0r-2007-profile/

For Outlook 2010 1. Open the start menu on the PC/Profile you are getting old autocomplete info from and type in:

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

2. The Auto Complete file starts with Stream_Autocomplete and ends in .dat with a string of alpha numeric in between.

3. Pay careful attention to the dates these were last edited. The correct Stream_Autocomplete file will have the most recent date. Copy the file from the old autocomplete PC/Profile.

5. On the new PC/Profile rename the Stream_Autocomplete file to Stream_Autocomplete….dat.old.

4. Copy the new Stream_Autocomplete file to the same location on the new PC/Profile.

6. Copy the old Stream_Autocomlete unique alpha numeric string “filename” From S up to .dat and replace the new one with that name.

Now you should be able to open Outlook with all of your autocomplete data.

Outlook 2010 doesn't store autocomplete suggestions in .NK2 files like older versions of Outlook. It stores the info in a hidden record in the PST file.

http://mfcmapi.codeplex.com

Session → Logon → Mailbox → Inbox

Right-click Inbox → IPM.Configuration.Autocomplete

Subject → Right-click IPM.Configuration.Autocomplete

Export Message → MSGFile Unicode

Record must be deleted before importing.

Session → Logon

Folder → Import → From MSG