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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
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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
Ron Metzger

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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

How to delete extend.dat using VSE8.x via ePO 4.0.x

This works for us. 2200 workstations and counting.

Thank you

Exactly what I needed. Excellent.
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