Thursday, 7 October 2010

Migrate Outlook Autocomplete address list to BPOS

What is Auto-Complete feature in Outlook?
One of the features that must be configured after migrating to BPOS is the Auto-Complete functionality. this feature is in fact a cache of all the email addresses you have used to send email to. to see this in action you can start sending an email and you can see Outlook is automatically completing people's names as you begin to type them in To box.
Why after BPOS deployment Outlook loses Auto-Complete feature?
Outlook uses profiles. configuration for each profile is only local to that profile. Auto-Complete is one of the features that is created per profile. when you install Microsoft Sign In application and it configures applications such as Outlook, what it does is actually creating a new Outlook profile which is configured to connect to Exchange Online. This new profile doesn't inherit the configuration you had on the existing profile, so features such as Auto-Complete need to be reconfigured.
 How to migrate Auto-Complete to the new BPOS account?
Auto-Complete information is stored in a file with .nk2 format. This is usually found in the place that Outlook stores its profiles. the best way to find the .nk2 file is to search for it. search should include hidden files. the .nk2 file has a same name as the Outlook profile name. The default name for Outlook profile is outlook, so the auto-complete file name will be outlook.nk2.
When BPOS is deployed and Sign In application is created a new Outlook profile, this profile generates a new .nk2 file for itself. The name of the profile that is created by Sign In application is usually "youremail.pst" (example: unless there is no profile named outlook.pst before. If Sign in application finds out that there is no profile called "outlook" then the BPOS profile will be named outlook. The best way to identify which profile is for BPOS is to look at the size. as BPOS is newly installed, the size of its profile will be much smaller than the old profile.
If the old profile name is outlook.pst and the auto-complete cache file name is outlook.nk2 and as an example let's say the BPOS profile name is and the Auto-Complete file name is then follow the steps below to migrate the auto-complete feature to the BPOS profile:
1.       close Outlook
2.       copy the Outlook.nk2 file and back it up
3.       rename the backup outlook.nk2 file to
4.       delete the original created by the Sign In application and replace it with the new (renamed outlook.nk2)
5.       start outlook
Now if you try sending an email, the auto complete feature will be there.


  1. This is only for Outlook 2007?
    Outlook 2010 has no .nk2 files.

  2. This is for Outlook 2003 and 2007. In outlook 2010, nk2 file is merged into outlook profile.
    If you want to migrate an autocomplete cache from previous versions of outlook to outlook 2010, follow these steps:

    1.Copy the nk2-file to the following folder;
    -Windows Vista and Windows 7

    -Windows XP
    C:\Documents and Settings\%username%\Application Settings\Microsoft\Outlook

    2.Rename the nk2-file to the name of your mail profile.
    To find out this name use the Mail applet in Control Panel and click on the Show Profiles… button.
    By default, your profile is called “Outlook”. So in that case you would call your file “outlook.nk2”.
    3.Start Outlook with the /importnk2 switch;
    -Windows Vista and Windows 7
    Start-> type; outlook.exe /importnk2

    -Windows XP
    Start-> Run; outlook.exe /importnk2

    4.Outlook will now process the nk2-file and import it into the Suggested Contacts folder. Outlook will automatically append .old to the nk2-file. So in our example it will now be called; outlook.nk2.old

  3. Amin, thank you for the additional info on the 2010 migration. That was very helpful and save me a lot of time...:)

  4. Amin, is there a way to "refill" a nk2 file from an existing mail-archive? We have recently migrated to BPOS and have replaced pc's/upgraded Outlook at the same time. Colleagues have been working with BPOS for two months now and some of them keep complaining about the missing auto-complete for existing clients.

  5. you can refill the nk2 files from archive if the archive includes the nk2 file. Please note that nk2 is not included in pst archives of outlook 2003/2007

  6. For outlook 2010 transfer to another profile

    Close Outlook. If you have the old Stream_Autocomplete file the old mailbox used - copy it to:


    Highlight the new file, hit F2 and copy the filename to the clipboard. Then delete that file. Highlight your old file, hit F2 and paste in the new filename.