You are prompted for a password and a user name when you view HTML messages in Outlook

If you open an HTML-formatted e-mail message in Microsoft Outlook, you may be prompted to enter your user name and password.

This problem occurs when the following conditions are true:

• You are connected to the Internet through a proxy server, and you are using basic authentication.
• The HTML-formatted e-mail message contains a link to graphics that are stored on an external server.
• The HTML code for the graphics link contains a user name and a password.

Under these conditions, Outlook will try to authenticate the links by using the user name and the password in the graphics link. This authentication will fail in most situations. After this problem occurs, if you try to view other e-mail messages that contain links to external graphics, Outlook prompts you again for your user name and password.

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To work around this problem, follow these steps:

1. Install the MS04-004 Cumulative Security Update for Internet Explorer (832894). This security update provides a new registry subkey that controls the handling of user information in a Hypertext Transfer Protocol (HTTP) or HTTPS URL.
   
   For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
   832894  (http://support.microsoft.com/kb/832894/ ) MS04-004: Cumulative Security Update for Internet Explorer
2. To apply the workaround for all Outlook users, you must add a new entry (msimn.exe) to the following registry subkey:
   HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_HTTP_USERNAME_PASSWORD_DISABLE
   To apply the workaround for a specific user of Outlook, you must log on as that user and then add the msimn.exe entry to the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_HTTP_USERNAME_PASSWORD_DISABLE
   To do this, follow these steps:
   1. Click Start, click Run, type regedit, and then click OK.
   2. Locate and then click the registry subkey that you want to modify.
   3. On the Edit menu, point to New, and then click DWORD value.
   4. Type msimn.exe, and then press ENTER.
   5. On the Edit menu, click Modify, type 1, and then click OK.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in Internet Explorer 6.