After installing Symantec Endpoint Protection, Microsoft Outlook displays an add-in error dialog

Issue

Following the installation of the Symantec Endpoint Protection (SEP) client, launching Outlook results in an error dialog: "The Add-in 'Symantec Antivirus Outlook Protection' (C:\Program Files\Common Files\Symantec Shared\vpmsece.dll) cannot be loaded and has been disabled by Outlook.  Please contact the add-in manufacturer for an update.  If no update is available, please uninstall the add-in." How can this be resolved?

Cause

The optional Outlook plug-in was not uninstalled correctly during the SEP installation process, potentially due to install-time file locking issues.

Solution

For greatest compatibility, always be sure that the most recent release of SEP is being installed.  Also ensure that a supported release of Outlook is in use.
At least two potential solutions for this problem exist.

(1) Delete the file C:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook\extend.dat and allow the file to be re-created when Outlook is started.

(2) Disable the Symantec AntiVirus Outlook Protection component from within Outlook:

1. In Outlook click Tools > Trust Center...
2. Click Add-ins
3. Choose Exchange Client Extensions from the Manage: drop down menu and click Go...
4. Uncheck Symantec AntiVirus Outlook Protection
5. Click OK.

Additional information can be found in Outlook attachments are unavailable with the AntiVirus Outlo