Remote IT Support

KB – Outlook Nicknames Feature


If you are using Outlook you will have noticed the feature that suggests email address as you start typing, as seen below.


The results of this suggestion feature in Outlook is stored in a file called the nickname file.


Earlier versions of Outlook store the nickname cache .nk2 file in the following folder.

  • Windows XP
    Drive:\Documents and Settings\Username\Application Data\Microsoft\Outlook
  • Windows Vista and later versions


The filename has the format <profilename>.nk2.  If a new profile has been created the file can be copied and renamed to the new profilename.


Outlook 2010 does not use the .nk2 file for maintaining your nickname cache. All updates to your nickname cache in Outlook 2010 are made to the hidden message in your default message store.


When Outlook 2010 is first run, it will import the .nk2 file into the hidden message and rename the .nk2 file to .nk2.old.


It is possible to force this import if further imports are required by using the outlook.exe /importnk2 switch. The name of the .nk2 file to be imported needs to be the same as the Outlook 2010 profile name.


In Outlook 2010 / Outlook 2013 there is a file created in the following location


This is created when a new profile is created.

This file and the NK2 file can both be viewed and edited using the Nirsoft NK2Edit utility.



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