What is NK2 File Extension?


It is a Microsoft AutoComplete Nick format. Its file extension is .nk2 which is easy to recognize. It is the tech giant Microsoft introduced NK2 files in Outlook 2002. Its updated version gives multiple options for contacts right after typing a name.


It belongs to more than one category. It is categorized in Email messages, Contacts and Address Categories.

Supportive Apps

It is a flexible file extension supported MS 2002 to all the latest versions of MS like 2010 and 2013.


It is the tech giant responsible to upgrade the file extension.


The hexadecimal signature of the file extension is 0D F0 AD BA 0A 00 00 00


As per the version of MS Outlook and Windows, the location of NK2 is changed.

For version 2002 to 2008 of Outlook, the location is -

In Windows 2000, XP, and Server 2003

C:\Documents and Settings\[User Profile]\Application Data\Microsoft\Outlook

In Windows Vista, Server 2008 and 7

C:\Users\[User Profile]\AppData\Roaming\Microsoft\Outlook

The latest 2010 to 2013 MS Outlook, the location is-

In Windows Vista, Server 2008 and 7

C:\Users\[User Profile]\AppData\Local\Microsoft\Outlook\RoamCache

How to view the NK2 File Extension

  • Users can open the file extension in MS Outlook.
  • In case, an NK2 file is damaged, a third party tool can repair and view the file.