You receive error messages when you start Outlook and send mails in Outlook 2000 (241817)


The information in this article applies to:

  • Microsoft Outlook 2000
This article was previously published under Q241817

SYMPTOMS

When you attempt to start Microsoft Outlook, you may receive the following error message and Outlook may fail to start:
Outlook caused an invalid page fault in module MSo9.dll at <memory address>

-or-

When you try to send e-mail, you may receive the following error message:
This program has performed an illegal operation and will be shut down. If the problem persists, contact the program vendor.
If you click Details, the following additional information is displayed:
Outlook caused an invalid page fault in module Mso9.dll at <address>
When you attempt to start Outlook, you may receive the following error message and Outlook may fail to start:
Outlook caused an invalid page fault in module MSo9.dll at <memory address>

-or-

Outlook has caused an error in MSO9.DLL

CAUSE

This problem can occur because the file Mso9.dll, common to all Microsoft Office 2000 programs, may be damaged or missing.

RESOLUTION

To resolve this problem, rename both the Outcmd.dat and Mso9.dll files, and then use the Add/Remove Programs tool to repair Outlook.

To Rename the Outcmd.dat File

  1. Windows 95 and Windows 98:
    Click Start, point to Find, and click Files or Folders.

    Windows Millennium Edition:
    Click Start, point to Search, and then click For Files or Folders.
  2. Windows 95 and Windows 98:
    In the Named box, type Outcmd.dat;views.dat, and then ensure that the entire hard disk is being searched. To do so, click My Computer in the Look In list, click Include Subfolders option, and then click Find Now.

    Windows Millennium Edition:
    In the Search for files for folders named box, type Outcmd.dat;views.dat, and then ensure that the entire hard disk drive is being searched. To do so, click My Computer in the Look In list, and then click Search Now.
  3. Right-click the file, and then click Rename.
  4. Rename the file by changing its file name extension to .old, and then press ENTER.
  5. Close the Find Files dialog box.

To Rename the Mso9.dll file

  1. Windows 95 and Windows 98:
    Click Start, point to Find, and click Files or Folders.

    Windows Millennium Edition:
    Click Start, point to Search, and then click For Files or Folders.
  2. Windows 95 and Windows 98:
    In the Named box, type Mso9.dll, and then ensure that the entire hard disk is being searched. To do so, click My Computer in the Look In list, click the Include Subfolders option, and then click Find Now.

    Windows Millennium Edition:
    In the Search for files for folders named box, type Mso9.dll, and then ensure that the entire hard disk is being searched. To do so, click My Computer in the Look In list, and then click Search Now.
  3. Right-click the file, and then click Rename.
  4. Rename the file by changing its file name extension to .old, and then press ENTER.
  5. Close the Find Files dialog box.

To Repair Outlook

  1. Click Start, point to Settings, and then click Control Panel.
  2. In Control Panel, double-click the Add/Remove Programs icon.
  3. In the list of installed programs, click to select either Microsoft Outlook or Microsoft Office, depending on how you installed Outlook.
  4. Click Add/Remove.
  5. After Setup begins, click Repair Office.
  6. Click Repair errors in my Office 2000 installation, and then click Finish.
The repair process may take several minutes while Office Setup repairs any damaged or missing files. If you receive a prompt to restart your computer, click Yes.

REFERENCES

For additional information about other causes of invalid page faults occurring in module Mso9.dll, click the following article number to view the article in the Microsoft Knowledge Base:

223607 Fatal error linking file to contact from Word

237912 Outlook stops responding when using Quick Find feature

240813 Errors when sending e-mail from an Office Program

Modification Type:MinorLast Reviewed:8/11/2004
Keywords:kbsendmail kbstartprogram kbprb KB241817
©2004 Microsoft Corporation. All rights reserved.