cancel
Showing results for 
Search instead for 
Did you mean: 

Outlook Add-On errors after 8.5 to 8.7 upgrade

i've seen this now on a couple of machines in our network.

i have a task that uninstalls any previosu versions of mcafee on the clients machine (8.0 and 8.5) and then installs the 8.7 software.

the problem that i am running into, is that if i push it out when the client has outlook open, they will get the following error message once the new software is installed and the next time they open outlook:

The add in "C:\Program Files\McAfee\VirusScan Enterprise\Scanotlk.dll" could not be installed or loaded. This problem may be resolved by using Detect and Repair on the Help menu

Granted the simple fix is to go in an disable the add-on for outlook. this is going to be a real pain if i have to do it to the 90 compters i have left to upgrade.

any suggestions ??
4 Replies
rmetzger Reliable Contributor
Reliable Contributor
Report Inappropriate Content
Message 2 of 5

Delete Extend.dat


The simple answer is to delete Extend.dat files from the 'documents and settings' folders.

Extend.dat is a 'performance' enhancement used by Outlook to load add-ons without the need of looking into the registry for loading instructions. When Outlook is open and you installed the McAfee Outlook Addon, Scanotlk.dll could not be cleared from Extend.dat. Now, every time Outlook loads it is using the cached information in Extend.dat to load a now missing Scanotlk.dll file -- thus the error message.

The good news is that the Extend.dat file is completely rebuilt if it is deleted. When Outlook is run the next time, it rebuilds Extend.dat using the settings in the registry to repopulate the correct information.

This needs to be done while Outlook is closed. I would suggest doing this from a login script, which should happen before Outlook is running.

del "%Userprofile%\Local Settings\Application Data\Microsoft\Outlook\Extend.dat"

As an administrator I use this:
del /f /s /q "%SystemDrive%\Documents and Settings\Extend.Dat"
You may need to alter this for Vista systems.

Hope this helps.
Ron Metzger
Thanks,
Ron Metzger

Was my reply helpful?
If this information was helpful in any way or answered your question, will you please select Accept as Solution in my reply and together we can help other members?

RE: Delete Extend.dat

Vista Line is:


del /q /f /s "C:\Users\%username%\AppData\Local\Microsoft\Outlook\Extend.dat"

RE: Delete Extend.dat

How to delete extend.dat using VSE 8.x via ePO 3.6.x
https://kc.mcafee.com/corporate/index?page=content&id=KB59988&actp=search&searchid=1240927986318

How to delete extend.dat using VSE8.x via ePO 4.0.x
https://kc.mcafee.com/corporate/index?page=content&id=KB60069&actp=search&searchid=1240927986318

This works for us. 2200 workstations and counting.

Thank you

Exactly what I needed. Excellent.
You Deserve an Award
Don't forget, when your helpful posts earn a kudos or get accepted as a solution you can unlock perks and badges. Those aren't the only badges, either. How many can you collect? Click here to learn more.

Community Help Hub

    New to the forums or need help finding your way around the forums? There's a whole hub of community resources to help you.

  • Find Forum FAQs
  • Learn How to Earn Badges
  • Ask for Help
Go to Community Help

Join the Community

    Thousands of customers use the McAfee Community for peer-to-peer and expert product support. Enjoy these benefits with a free membership:

  • Get helpful solutions from McAfee experts.
  • Stay connected to product conversations that matter to you.
  • Participate in product groups led by McAfee employees.
Join the Community
Join the Community