We use Outlook 2010 and 2013 connected to Microsoft Office365 (corporate accounts). We imported a big address book. Every account has access to it, no problem there.

I search a way to use auto-complete from this address book when people type an email address.

The usual trick is: create a new email, add every contact to the "A" field, then close the email.
It works as long as Outlook remains open. Once Outlook is restarted, only the old auto-complete remains.

Is there a way to "import" contacts into the auto-complete cache ?

We tried what appear to be the usual trick: manually remove the Stream_Autocomplete.dat file then restart Outlook. Then Outlook recreate the file. But in our case the file is not recreated and the problem remain the same.
We also tried to clear the autocomplete cache (from Options/Mail/...), uncheck the use of autocomplete, restart Outlook, recheck autocomplete. This hasn't solved the problem.


The Software "NK2Edit" edits nk2 and stream_autocomplete.dat files. It allows you to import a complete adressbook into the file, edit and delete certain rows etc. http://www.nirsoft.net/utils/outlook_nk2_edit.html (Download is at the bottom of the page)


You can follow Microsoft's guide from here which tells how to copy an autocomplete file from one PC to another.

In summary:

Copy the file with an nk2 extension from the old PC. This will be in the %APPDATA%\Microsoft\Outlook folder.

Copy the file onto the new computer in the %APPDATA%\Microsoft\Outlook folder for the profile of the person you wish to have the list.

Rename the file to match the profile name

Invoke Outlook using the command outlook /importnk2

  • nk2 files don't exist anymore since Outlook 2010. This is now Stream_Autocomplete.dat – Gregory MOUSSAT Jan 17 '14 at 18:07
  • 1
    The question is not about the transfert of autocomplete file. It is about the fact it is not saved when Outlook is closed. – Gregory MOUSSAT Jan 17 '14 at 18:25

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