This article was previously published under Q240813
This article has been archived. It is offered "as is" and will no longer be updated.
When you attempt to send e-mail from a Microsoft Office program, Microsoft Internet Explorer, or any program that supports the Simple Messaging Applications Program Interface (MAPI) transport, 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 displays:
Outlook caused an invalid page fault in module Mso9.dll at <address>.
You installed the Outlook Personal Folders Backup Utility, and Outlook was not running at the time you attempted to send the message.
Start Outlook before attempting to send an e-mail message from another program.
Uninstall the Microsoft Outlook Personal Folders Backup utility.
Follow these steps to uninstall the utility:
On the Tools menu, click Options.
On the Other tab, click Advanced Options.
Click COM Add-Ins.
Click to clear Outlook Backup Addin.
Click OK three times to close the Options.
Click Exit on the File menu.
The error message sequence in the "Symptoms" section will be followed by one of the following depending on the selection made on the Send To menu:
If you chose Send To Mail Recipient, the message will read:
<application> could not load the e-mail envelope. This could be caused by a network connection problem or a problem with your Office installation.
If you chose Send to Mail Recipient (as Attachment), the message will read:
<application> couldn't send mail because of MAPI failure: "Unspecified error".
For additional information about the Personal Folders Backup Utility, please click the article number below to view the article in the Microsoft Knowledge Base:
238782 OL2000: How to Automatically Backup Your Personal Folders File
For additional information about other causes of invalid page faults occurring in module Mso9.dll, please click the article numbers below to view the articles in the Microsoft Knowledge Base:
223607 OL2000: (CW) Fatal Error Linking File to Contact from Word