Microsoft Outlook error: "The add-in 'C:\Program Files\NavNT\vpmsece.dll' could not be installed or loaded . . ."

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Article ID: 178201

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Updated On:

Products

Symantec Products

Issue/Introduction

When you start Microsoft® Outlook®, you see the following message:

"The add-in 'C:\Program Files\NavNT\vpmsece.dll' could not be installed or loaded. This problem may be resolved by using Detect and Repair on the Help menu. Unable to load "C:\Program Files\NavNT\vpmsece.dll". You may be out of memory, out of system resources, or missing a .dll file."

Using the Detect and Repair option, as suggested in the error message, does not solve the problem.

Resolution


Before you begin: If you see Symantec_Client_Security in the error message instead of NavNT, or if you are using Symantec AntiVirus 9.x, read the following document instead of this one: Error: "The add-in 'C:\Program Files\Symantec_Client_Security\Symantec AntiVirus\vpmsece.dll' could not be installed or loaded . . ."

To fix the problem, find and delete all copies of the Extend.dat file on the computer. A copy of this file exists for each user account. Then, restart the computer.


Note: You cannot delete copies of the Extend.dat file for other user accounts unless you log on with an account that has local administrator rights.



To find and delete copies of Extend.dat
  1. Exit Outlook if the program is open.
  2. Confirm that Windows is set to show hidden and system folders.
    To show hidden and system folders, read How to make Windows show all files.
  3. On the Windows taskbar, click Start > Search > For Files or Folders.
  4. Under "Search for files or folders named," type the following text:

    extend.dat

  5. Click Search Now.
    Wait for the search to finish.
  6. Delete all copies of the Extend.dat file.
  7. Restart the computer.

If a Group Policy that hides system files is in effect, you may not find the Extend.dat file when you search or browse, even after you set Windows to show all files. If you do not find any copies of the Extend.dat file, use a command prompt to delete the file(s).

To find and delete copies of Extend.dat from a command prompt
  1. Exit Outlook if the program is open.
  2. On the Windows taskbar, click Start > Run.
  3. In the Open box, type cmd and then click OK.
  4. At the command prompt type the following command and then press Enter:

    cd %appdata%


    The prompt shows the Application Data folder for the current user.

  5. Type cd microsoft\outlook and then press Enter.

  6. Type del extend.dat and then press Enter.
  7. Delete the Extend.dat file for every user account on the computer.
  8. Restart the computer.


Note: On some versions of Windows, a user folder called LocalService is present. For example, on Windows XP, you may need to delete a copy of the Extend.dat file from the folder \Documents and Settings\LocalService\Local Settings\Application Data\Microsoft\Outlook.





Technical Information
This problem happens because the Extend.dat file contains cached information. Outlook does not update the contents of the file when you start Outlook. When you delete the Extend.dat file, Outlook creates a new copy of the file with current information from the registry.



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