Clear the Outlook Email Address Auto Complete Cache
Aug 1st, 2007 by MrGroove
Background: Outlook 2003 and Outlook 2007 has a feature called Email Address Auto Complete. As you type in an email address into the TO: or CC: field (and BCC: field I imagine) outlook will display a list of matching email addresses from the outlook auto-complete cache.
Here’s an example:
![]()
As convenient as the Auto Complete feature is, there are times when you need to remove these cached email addresses from the cache. Perhaps you just sent an email and you found out you made a typo….. Unfortunately that typo will remain in you cache until you delete it.
Solution: The fix is easy:
- Type the email address you wish to clear from the cache until outlook displays it as shown above.
- Press the down arrow key to select the email address and press the delete button.
- All Done
Another option if you want to delete all addresses in the cache file (outlook.nk2):
- Close Outlook
- Open Windows Explorer or IE and Paste %APPDATA%\Microsoft\Outlook into the address bar.
- Delete the file Outlook.nk2 file in this folder
- All Done Groovy!
Tags: auto complete, cache, client, howto, microsoft office, outlook 2003, outlook 2007
Visitor Options

Exactly what I was looking for. Found the outlook.nk2 and blew it away! Thanks for getting this out!
Love the post. Another great writeup.
Welcome DJ & POneil!
Glad to see the article helped you out.
We did a migration of email from one domain to another. Everything pretty much has came across flawlessly. One minor issue we have is people aren’t able to display their contacts through the address book. I look at the contacts properties and the click on the permissions tab and the place to check to use this floder as an address book is grayed out. How do I activate this box? The user has permission on their computer and their email to make changes but for some reason this box is grayed out for several users.
Thanks for your help.
Dan
Hi,
Autocomplete option is enabled in my outlook but the cache gets cleared once almost every month. How can I stop this?
- Prashanth DN Kannadiga
That’s very odd. First we need to figure out if it’s being deleted or corrupted….
Look in the folder: %APPDATA%\Microsoft\Outlook\outlook.nk2 and find the file date of the outlook.nk2 file. What is it?
Also, it might be easier Prashanth to move this conversation into the Forum. Keeps from getting the comment system here to cluttered.
Does anyone know how to stop auto complete regenerating its new .NK2 file once you’ve cleared it?
I want to turn the function off all together… I know this can be done in previous versions of Outlook, but not 2003.
Thanks.
Welcome to the site DW.
The process is simple, in fact I’ve already written a how-to on disabling the auto complete feature for outlook 2003 and 2007. Here’s the URL: http://www.groovypost.com/howto/microsoft/outlook/disable-microsoft-outlook-2007-and-2003-email-auto-complete/
I seriously wanted this single delete from cache to work. I tried it so many times I’m crazy. I begin typing the name. I arrow down to it in the list. I hit delete. It goes away from the list. The next time I start to type the name, again, it comes back. Here’s the deal. I built an e-mail box with someone’s name and then changed the ‘resolve’ name, later. The address is the same, the resolve name is not. That’s what I’m trying to deal with. Ideas?
@ Renee: I’m not sure I understand your question fully but it might have something to do with caching in your GAL or how the account is setup in Active Directory.
If you want to continue troubleshooting the problem, please create a thread here: http://www.groovypost.com/forum/microsoft-office-f54.html This comment system is not a great “forum” for troubleshooting issues.
Thank you… You are da man!
@ SigEp
Thanks and Welcome to the site!
This answered my question, and worked right away! Nice post!
I can’t believe that expertsexchange.com (Expert Sex Change) charges for someone to read how to do this! I think your post should be #1 in the search. Those guys are a joke. Just my opinion on that, well said and helped me out a lot! Maybe I will stop sending e-mails going to my new boss to my old one. My fault for not finding one named differently.
Take care,
Chad R. Smith
President of Get A Supplier INC
http://www.getasupplier.com
How about clearing cache for Outlook 2000 is it the same
How do you enable the cache. It was there, but now no names pop up when a letter is pressed. the nk2 files is not deleted because I see it under the profile name and the option is enable in outlook email options. Please help!
Phew, needed to hide address from my wife for a suprise, without this i would be in trouble
THANKS
@RugbyBoy14 - Welcome to the site!
Excellent! I’m glad it helped you out! BTW - If there’s ever something you can’t figure out, feel free to post in the Forum!
I have Office 2007. There are three files titled Outlook but they are an SMS, XML, and a Outlook Data File. Are any of these the ones I am looking for? If not, how would I go about clearing the cache for the 2007 version?
@Danger Dave,
First, Welcome to the site Dave. Second, the article is actually written using my Outlook 2007 client. With that said, if you do a search on your hard drive for outlook.nk2 you should find all instances of the outlook cache file. If you delete the files you find you should be good to go.
Thanks a lot!! I have been trying to delete obsolete names without positive results. Now, I know how to do it!!!
GOD bless you!
@Pilar & Jffga - Welcome to the site and thank you for your comments! I’m glad the article was beneficial!
Superb! was looking for a fix for ages
Thanx
@Raj - Excellent! Thanks for the comment!
[...] When I first ran into this problem, the first thing I did was delete my .nk2 file (Check HERE for instructions on where to find the .nk2 file) thinking that perhaps mine had become [...]
groovy man! love the post.
This method helped me a lot.
Thanks
Re removing pesky names that show up (and are incorrect) in auto complete
Groovy
Tried both options above. No can do.
The extenstions that show up in option 2 are:
.dat and .srs no .nk2
Help!
I got the auto complete to cease after some playing .
Thanks Groovy
Bruce
thanks. i was able to save my email entries. great help
AWESOME!
BEEN LOOKGIN FOR THIS for like 2 months!!!!
Thanks, you are a life saver my friend and you rock!
Is there a way to copy all the emails in your cache. I’m leaving my current job, and want to keep a list of all the contacts I’ve made over the years, but I don’t have them all in my address book. Is this possible. Just want a list, not a file, to transfer over to my personal computer.
@Mike
You have a few options. What ever you do, be sure to grab a copy of your .nk2 file. You can find the location in the Tutorial above.
My recommendation would be to grab a copy of NK2View from http://www.bestsoftware4download.com/software/k-utility-t-free-nk2view-download-zkgzeysf.html
At the time of this writing, the latest version of NK2View is 1.20. After you download the software, just run it from any folder and it should find your NK2 file. You have a few options to either Save the list of emails into a TEXT file or copy them into your address book. You can also point the app at another Outlook .NK2 file and convert it as you like.
Hope this help!
@Bruce - Glad to hear you figured it out. Let me know if you have any other questions!
Having deleted Outlook.nk2, how do I put it back should I want to?
@Robert - Hi Robert, if you deleted the .nk2 file, it’s pretty much gone unless you saved a copy of it. Did you save it somewhere? Also, what OS are your running? Vista or XP?