If you are using Outlook then you must have used Nickname Cache (NK2) feature regularly. Well now if you are confused what is this Nickname Cache (NK2) is, then its  data or to be more precise the email id’s or addresses  stored in Outlook  which is used to auto-complete email addresses when you are type  email addresses into  the To or Cc field.

These are not the contacts which you have saved yet it’s always there right and its one of most useful feature of Outlook right?  Outlook stores this as a cache data as .NK2.  NK2 file is stored in hidden folder user’s profile in drive: \Documents and Settings\user name\Application Data\Microsoft\Outlook.

With this file storing email addresses, next time when you type the same email address it comes beneath you’re To, CC or BCC felid and you can select the same and avoid the pain of typing it again and again.

How to Backup: Now suppose you are formatting your computer or by any reason crashed then you need to navigate to the path mentioned above and then copy it and save it. This file will be with the extension .NK2 and it can be viewed only when you enable view hidden files in Windows. (Note: If you are using Windows Vista or 7 then location will be C:\Users\[user name]\AppData\Local\Microsoft\Outlook\RoamCache). Now you can save the copy and restore it back to same directory once you have installed fresh copy of Outlook.

How to edit, Backup with free utility:  At times there may be situation when you cannot use original NK2 file like sometimes you have migrated to different exchange server or changed the email id of a group of people, if you use the same old NK2 file and then you use the same autocomplete features then you will get NDR (Non delivery report) ,email bounce etc. That’s when you need to edit Nk2 files where you can remove specific email addresses which have changed and then restore back.

Now this is important since other than the mail ids changed there will lot of addresses which may be important for you and unfortunately you have not saved them in your contacts.

Nk2view .exe is excellent freeware application which helps you out in these situations; Nk2view is simple and light portable application which can be used to view your NK2 files, delete the entries, save the NK2.

This tool is extremely helpful and I would recommend it for all above situations.

Grab this freeware: Download NK2 View.

Hope this article helped, do comment. 🙂