http://www.itsupportguides.com/office-2010/transfer-outlook-2010-auto-complete-to-new-computer/

Outlook has an function to suggest email addresses as you start to type them in, commonly known as the ‘auto-complete’ feature.

It works by keeping a list of people you’ve emailed so when you go to write a new email address and start filling out the ‘to’, ‘cc’ or ‘bcc’ field it will suggest the similar email addresses.

Previous versions of Outlook stored this list in a file called ‘Outlook.nk2′ however Outlook 2010 now uses an XML file called ‘stream_autocomplete’.

Transferring the file to a new computer or user profile is a simply copy and paste process:

Please Note: Outlook needs to be closed

1. First you need to find the file. The location may be different depending on if you’re using Windows XP or Windows 7/Vista:
   1. Windows XP -  C:Documents and Settings%username%Application DataMicrosoftOutlookRoamCache
   2. Windows 7 / Vista – C:Users%username%AppDataLocalMicrosoftOutlookRoamCache
2. The file will start with ‘Stream_autocomplete’ followed by a string of hex numbers
3. 
4. Copy the file to a safe location, e.g. a USB drive
5. On the new computer or user open the same folder location and paste in the file:
   1. Windows XP -  C:Documents and Settings%username%Application DataMicrosoftOutlookRoamCache
   2. Windows 7 / Vista – C:Users%username%AppDataLocalMicrosoftOutlookRoamCache
6. Open Outlook and check the the auto-complete has been successfully transferred.