How to Update Auto complete Option to New PST file in Outlook?

Make sure you exit Outlook before starting the following procedure. The names will be included in auto-complete when you restart Outlook.

Open the start menu. The autocomplete files start with Stream_Autocomplete and end in. at .There maybe multiple files but the one with the most recent date should be the current one used by the last Outlook profile you created. With Outlook closed (very important), copy the full file name of the current (empty) Auto Complete file. You may want to copy this file name into Notepad. Now delete the file. Copy the slightly older file that contains the auto-complete data you need. Finally rename this copy to the file name you just copied (which is in notepad).You should now have the same files as before but the current auto-complete file should be a copy of the last working one and share the modified date and time

1. Make sure that the .nk2 file is in the following folder: %appdata%\\Microsoft\\Outlook. ...
2. Press Windows Key + R to open the Run dialog.
3. In the Open box, type (or paste) outlook.exe /importnk2, and click OK to import the NK2 into your profile.

Windows 7    Click Start {picture}. Next to the Shut down button, in the Search programs and files box, type outlook /importnk2 and then press Enter.