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Fix Slow Outlook Email Address Auto Complete

Microsoft Outlook 2007

OH MY GOD! Outlook Auto Complete is SOOO SLOW!  HELP ME!!  <phew> got that out.  The good news is I have the fix.  Thanks to a bug with McAfee, Outlook 2007 (and possibly 2003) users will experience SEVERE lockups (3-10 seconds) and delays while typing in email addresses or deleting email addresses in Outlook.  The larger your Outlook Auto Complete cache file (.nk2) the longer you will wait.  Before I found this fix I was ready to remove Outlook 2007 and go back to 2003……


Let’s get to the FIX:

The issue is a result of how the new McAfee Buffer Overflow Protection interacts with the Outlook automatic completion feature.

To fix the problem you need to tell McAfee to Exclude outlook.exe from the Buffer Overflow protection:

Add an exclusion locally for outlook.exe under Buffer Overflow Protection settings:.

  1. Click, Start, Programs, McAfee, VirusScan Console.
  2. Right-click on Buffer Overflow Protection and Select Properties.
  3. With the Buffer Overflow Protection tab selected Click Add.
  4. In the Process name field type the following: outlook.exe then click OK.
  5. Click Apply then OK to close the Buffer Overflow Exclusions window.
  6. Fixed! CAN I GET AN AMEN!!!

Additional Background/Information


1. Please note, in my case, my notebook was installed with:

  • Microsoft Vista Enterprise Edition
  • Microsoft Outlook 2007 (errr… Office 2007)
  • McAfee VirusScan Enterprise 8.5.0i


2. If your computer is attached to a company network, there is a chance that these settings will be grayed out. In these cases, your computer is probably managed by the McAfee’s enterprise management product (EPO) or, when McAfee VirusScan was installed, a password was used to lock the config.  In either of these cases you will need to contact your Systems Administrator or Helpdesk for assistance.


3. 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 corrupt.  Although this was a “temporary” fix, once the file grew in size I began having performance problems again with the auto-complete function.  Just an FYI from MrGroove 🙂


This is one of my more GROOVY articles!


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43 Responses to Fix Slow Outlook Email Address Auto Complete

  1. Marcel July 30, 2007 at 12:43 am #

    Thanks, this solved an extremely irritating problem.

  2. MrGroove July 30, 2007 at 8:42 am #

    Trust me, I understand 110% Marcel!

    I spend 1/2 my day in outlook these days… … so before the fix I was ready to lose my mind. Then there’s the users who were beginning to riot in the halls with pitchforks…….

    Glad the article helped you out!

  3. Mike August 23, 2007 at 2:01 am #

    You deserve a medal. This was driving me completely potty – was starting to think I would never find an answer.


  4. MrGroove August 23, 2007 at 8:25 am #

    Thanks Mike. Personally, had it taken another “day” for me to find the fix I was ready to uninstall Outlook 2007 and fallback to Outlook 2003 on my work machine…

    Glad it helped you out!

  5. MonsterP August 24, 2007 at 2:03 am #

    Thanks MrGroove,
    I’m so glad I found your tip. Slow autocomplete has been crippling me since I upgraded and getting worse.
    Excellent advice.


  6. Leo September 5, 2007 at 8:10 am #

    Thanks! for this fix!
    It eluded me for several months how to fix this.
    Now Outlook works just fine again.

  7. Converted September 12, 2007 at 6:31 pm #


    You just saved my life. My entire IT org. was working on this STUPID problem! Thank you very much mrgroove!

  8. Jameson September 24, 2007 at 2:18 pm #

    Life Saver!!! Thanks you very much.

  9. MrGroove September 24, 2007 at 5:28 pm #

    Glad the article helped you out!

  10. simonsays October 10, 2007 at 4:51 am #

    This morning I came very close to throwing my monitor through the window. Thank you *so* much for this fix!

  11. MrGroove October 10, 2007 at 7:54 am #

    Excellent! Welcome to the site Simon.

  12. Aryn October 17, 2007 at 2:36 am #

    This fixed worked a charm thank you!

    Machine setup:
    Win XP Pro SP2
    McAfee 8.5.0i
    Outlook 2007 with all updates
    Original NK2 file size is\was 1.2MB

    Thanks again, would have probably ended up reinstalling Outlook in the end.

  13. MrGroove October 18, 2007 at 10:24 am #

    Excellent! Aryn! And welcome to the site!

  14. Mike October 23, 2007 at 6:49 am #

    Good job, thanks!

  15. Mark October 29, 2007 at 8:05 pm #

    I don’t see a “Buffer Overflow Protection” tab in the VirusScan console.
    My operating system is Vista…if that helps.
    Any ideas???

  16. MrGroove October 30, 2007 at 5:23 am #

    Hi Mark and Welcome to the site!
    What version of VirusScan are you running? You should be able to right click on your virusScan shield and click “about” to get the version number.

  17. Mark October 30, 2007 at 3:12 pm #

    Thanks for the prompt response.
    I’m running version 8.5.0i

  18. MrGroove October 30, 2007 at 11:23 pm #

    No problem Mark. For this kind of Tech support, I think the forum is a better place to answer your question. Let’s move the discussion there being that the Forum is really the right place for Tech support questions and discussion.

    I’ve created the topic here:

    Just register real fast and let’s continue the conversation and fix the issue!

  19. Mark October 31, 2007 at 8:12 am #

    I followed the link above to the forum. For some strange reason, the tab “Buffer Overflow Protection” does not exist in the console. All of the other tabs are there except that one. I tried to register on the forum website, but I couldn’t log in after registering. I will try again later to see if my information has gone through.

  20. Ashish November 4, 2007 at 11:52 pm #

    Thank you for posting this fix! This did the trick for me.

    I also used this opportunity to clear out the Outlook Auto Complete cache (Documents and Settings\username\Application Data\Microsoft\Outlook\Outlook.nk2). While this will be a pain in the short term as I build it back up, things are very responsive again and like many others I’m not ready to chuck things out the window!

    I’m not sure why this started happening all of a sudden (within the last week or so) when I’ve had Outlook 2007 running for months. Perhaps our IT organization pushed out something with McAfee that impacted this??

  21. MrGroove November 6, 2007 at 11:26 pm #

    Welcome to the site Ashish!

    Sounds odd but I think your right. Your IT guys must have pushed out something. You should give them the link so they can adjust the policy (if it makes sense for your org.).

  22. Matt November 15, 2007 at 12:40 pm #

    This is in no way a fix.. This is disabling a vital part of McAfee protection. I dont know about you all but I would rather wait for a update from McAfee than turn off my buffer overflow protection and more than likely have your computer be fully compromised by the many zero day exploits/worms/viruses floating around in the form of emails making thier way to your outlook inbox.

    You might as well unistall McAfee because most viruses come from email especailly outlook which has many security holes….

  23. Matt November 15, 2007 at 12:42 pm #

    and I have no problem with my auto complete, VSE 8.5 here….

  24. MrGroove November 17, 2007 at 12:56 pm #

    Welcome to the site Matt and thanks for the comments.

    I agree, that by disabling buffer overflow protection in outlook you are opening up an attack surface for your computer. That being said, I don’t agree that this change to the AV client introduces an unacceptable level of risk for the average user or corporation.
    The primary method which malicious emails infect the desktop are through attachments and malformed/malicious HTML. With this in mind, there are several ways which Outlook protects you from these threats such as Disallowing Programmatic Access, Disable of attachment preview and my Favorite, the option to convert all email to Plain Text prior to displaying it to the user. That being said, each user/company will need to make their own decision based on benefit vs. risk and the level of risk they are willing to accept. For me personally, I see this as very low risk (otherwise I would not have recommended it to my users).

  25. Robert December 5, 2007 at 11:57 am #

    You rock! Worked for me and the complaints can now cease! Amen, Brother!!

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