Technically Speaking

Microsoft Outlook carries a great deal of convenience for its users.  Some of these conveniences, like calendar, mail, tasks, and contacts in the same application are available from a majority of similar applications, but Outlook handles them really well.

The focus for this post is on the NK2 file and what it brings to the user, convenience, and also on making sure it is managed well by IT.

what the heck is the Nk2 file?

This file is where Outlook stores e-mail addresses as they are used.  For example, if I send an email to mike@myemail.com to catch up with a friend and then send an email to matt@widgetsplus.com to order parts for a project, the email addresses are plunked into the Nk2 file.

From then on, if I start typing an email address with m as the first letter, a dropdown list appears in the To: line of my message containing all of the entries in the NK2 file that begin with the letter M.  This feature is very very handy, but is not the best implementation of the address list.

Note: It has been said that Microsoft is working to incorporate this list of used addresses into the Outlook application for the Office 2010 release, making the Nk2 file go away.  I am curious to see what happens there.

Why do users care about this file?

Users in general do not care about the Nk2 file specifically, they only care about the list of addresses kept in the file.  Think of this as a makeshift contacts list.  Why would the vast majority of people put a contact into Outlook, when the list just appears as they begin entering addresses?  That is a huge waste of productivity and time.

When something happens to the Nk2 file for one or more of the users you support, it is likely that you will hear about it.  When I first experienced Nk2 atrophy I didn’t even know where to find anything about “the wiped out drop down list of addresses I need to send email”.  I spent a good amount of time learning that the dropdown list was contained in the NK2 file, stored within the cavern that is Outlook application settings within the user profile.

Will this file save the day?

It can be quite the safety net for a good majority of Outlook Users, but the contacts folder is the best place to put addresses.  Relying on a single file with no default backup is not a good idea, although most users (and sometimes myself) do it every day.

You can create a backup of this file for your users by copying the file to the network on regular intervals, which is highly recommended.  This way, if the list of addresses goes empty, the nk2 file can be copied over the old one and should be back to normal when Outlook restarts.

Note: In my organization we use Desktop Authority to manage the user experience, it copies the nk2 file to the users home directory when they logoff every day. When they logon, the local and remote files are compared and the newest one wins.  If that is the remote, due to locally corrupt or deleted file, the file is copied during logon and the list works as needed.

Using a scheduled copy script on regular intervals will accomplish the important part of the task, the backup.  Then when the user notices the issue, you can copy the backup to their machine and restart outlook.  Presto! Working address lists.

Creating a backup copy of the file

To get a backup of a users Nk2 file you simply need to copy it to another location.  Using a utility like xcopy works very well here, but remember to run the operation when the file is not in use to catch any entries that may get added (and make the process much smoother).

The local Nk2 file lives at c:\documents and settings\<username>\application data\Microsoft\Outlook

and is typically named according to the Outlook Profile (usually a userid).

so the source portion of your xcopy operation might look something like this:

Xcopy “c:\documents and settings\<username>\Application Data\Microsoft\Outlook\username.nk2”

Note: <username> represents the user id of the user whose Nk2 file you need to copy.

Add the destination to the xcopy script, typically the users home directory, I usually use a mapped share for this:

Xcopy “c:\documents and settings\<username>\Application Data\Microsoft\Outlook\username.nk2” “U:\<username>\<username>.nk2”

Then specify the needed xcopy options for the job, typically just /Y to prevent prompting to copy.

Save the file and schedule it to run for your users.  This way newer copies of the local nk2 file will overwrite older ones on the network, keeping the most recent copy backed up and on tape with the rest of the data.

Using the backup

Now that the nk2 files are backed up, if the user loses their address drop down list, you can quickly rescue them by copying the file back to the local application data folder.  Then when they restart Outlook all should be well.  Since the copy only takes a few minutes (depending on file size and bandwidth) you might have the user close Outlook then copy the file.  This way when started again the list should reappear and the user will be back to normal again.

Being the type of administrator who assigns accountability to files created by users, i.e. they have to get their files saved to the network for backup to happen, I have found this a very good idea because the user is not likely to know about this file if they can get to its location.  Automating this backup has proven very helpful for both my IT department and my users.