OL98: ErrMsg in Extension Configuration File Starting Outlook

When you attempt to start Microsoft Outlook 98, you may receive one or all of the following error messages: -or- -or-

The above errors result from either a damaged or missing .ecf or .dll file, or incorrect information in the Extend.dat file.

To correct this problem you may have to replace the damaged extensions, or you may have to remove the reference to them in the Windows Registry. If the problem persists, you should rename and recreate the Extend.dat file, which is a binary cache of extension settings.

To Replace the Damaged Extensions

1. Quit Outlook.
2. Insert your original Setup CD into the drive. If you installed from the web this will not be necessary.
3. In the \Program Files\Microsoft Office\Office\Addins folder on your computer, rename the problem .ecf file(s) referenced in the error message.
4. Click Start, point to Settings and click Control Panel.
5. Click to open the Add/Remove Programs icon.
6. Click to select Microsoft Outlook 98 and then click Add/Remove.
7. When prompted, click "Rerun Outlook 98 Setup". This will replace the .ecf files that were renamed earlier.
8. Restart Outlook.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

To Remove the Registry Entries

To remove the reference to the files in the Windows Registry, follow these steps:

1. Quit all programs.
2. On the Windows Taskbar, click Start and then click Run.
3. In the Open box type, regedit.exe.
4. Navigate to the folder:
   HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Client\Extensions
5. You will see the add-ins listed on the right under the heading of DATA. Click to select the name of the Data key that corresponds to the Addin referenced in the error message and press DELETE to delete this registry key.
6. On the Registry menu, click Exit.
7. Restart your computer and then restart Outlook.

Refreshing Extend.dat File

If you still receive the error message when you restart Outlook you must refresh the Extend.dat file, which is a binary file that caches the registry extension entries.

To refresh the Extend.dat file, follow these steps:

1. Quit all programs.
2. On the Windows Taskbar, click Start point to Find and click Files or Folders.
3. In the Named box, type "extend.dat" (without quotation marks.)
4. In the Look In list, click to select your hard drive.
5. Click to select Include subfolders and click Find Now.
6. In the Name list, right-click on the file Extend.dat and on the shortcut menu, click Rename to rename the file to Extend.old.
7. On the File menu, click Close to exit Find File.
8. Restart Outlook. Restarting Outlook creates a new Extend.dat file.