stream_autocomplete*.dat missing


  • I have a Windows 7 (32bit) computer running Outlook 2010, with an exchange account. It is currently not retaining the autocomplete cache for email addresses. Outlook will cache the email addresses for the session that is open, but as soon as you close the session the cached addresses are lost.

    In previous versions of Outlook the NK2 file held this data. As I understand the NK2 file has been replaced by stream_autocomplete*.dat located in the following directory:


    The problem: The "stream_autocomplete*.dat" file is missing from the directory listed above. I have scanned the machine with a file search and it is nowhere to be found. I have hopelessly tried to (auto)generate the file but am shooting in the dark.

    Is there any method for forcing Outlook to create this needed file? Or are there any other suggestions as to what might resolve this issue?


    Friday, February 11, 2011 5:08 AM


  • After further research I found a sufficient answer.

    Here's how I generated the missing  stream_autocomplete*.dat file



    With Outlook 2010 closed, I copied an existing NK2 file from a previous version of Outlook (2007 to be exact) to the following location:


    (NOTE: This location is different than where the resulting stream_autocomplete*.dat will be generated).


    I then renamed the NK2 file to match the profile name ( e.g. exchange.NK2 ). 

    From the RUN command window (WINDOWS KEY + R) type:  OUTLOOK /IMPORTNK2

    At this point Outlook 2010 will open. If the import was successful you should now see the stream_autocomplete*.dat file that is generated in



    I have verified that the cached addresses from the imported NK2 file list themselves when composing a new email, and in addition are retained when the Outlook session is closed, then reopened.



    • Marked as answer by IronGold Tuesday, February 15, 2011 9:41 PM
    Tuesday, February 15, 2011 9:40 PM