How to download and install

1. Select an item from the drop-down list above and click Download Now.
2. Choose Run this program from its current location and click OK.
3. Click Yes if asked whether you would like to install and run Outlook Express Security Update.
4. Click Yes to begin the installation process.

Important If you have a version of Outlook Express other than those listed above, your computer is still vulnerable. Microsoft recommends that you upgrade to the latest version of Internet Explorer.

Read This First

Computers running Outlook Express 5.5 are not vulnerable to this issue. Outlook Express 5.5 includes this update.

This update resolves the "Persistent Mail Browser Link," "Cache Bypass," and "Malformed E-mail Header" security vulnerabilities in Outlook Express. Download now to prevent a malicious user from reading e-mails and files on your computer, or using your computer to send damaging e-mails to others. These vulnerabilities do not give a malicious user the ability to add, change, or delete files on your computer.

For more information about this update and the issues it resolves, please read Microsoft Security Bulletins MS00-043, MS00-045, and MS00-046.

System Requirements
This update resolves the vulnerabilities in Outlook Express 4.01 Service Pack 2 (SP2) and Outlook Express 5.01 only. To verify which version of Outlook Express you have on your computer:

1. Click Help in the Outlook Express File Menu and then click About Outlook Express.
2. Apply this update if Version: is displayed as
   • 4.72.3612.1700 for Outlook Express 4.01 SP2, or
   • 5.00.2919.6600 for Outlook Express 5.01 (if you are running Windows 2000, the Outlook Express 5.01 version number will display as 5.00.2919.6700).
3. If Help About does not display one of these version numbers, you should upgrade to the latest version of Internet Explorer to resolve these issues.

How to uninstall
Uninstall is not available.