This article has been archived. It is offered "as is" and will no longer be updated.
On a computer that has Microsoft Office Outlook 2003 installed, external content is always blocked for attached e-mail messages after you install security update 949031 (security bulletin MS08-015).
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To resolve this problem, apply hotfix package 959628, and then configure the DisableSenderTypeSecurity registry entry to enable the hotfix package. To do this, follow these steps:
Apply hotfix package 959628. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
959628 Description of the Outlook 2003 hotfix package (Outlook.msp): December 16, 2008
Configure the DisableSenderTypeSecurity registry entry. To do this, follow these steps:
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry subkey:
On the Edit menu, point to New, and then click DWORD Value.
Type DisableSenderTypeSecurity , and then press ENTER.
Right-click DisableSenderTypeSecurity , and then click Modify.
In the Value data box, type 1, and then click OK.
Exit Registry Editor.
Note If the original sender of the attached e-mail message that has the blocked content is not someone from your own Exchange organization, the images may still be blocked. In this scenario, you have to add the domain name of the sender if you want Outlook to automatically display the images in the attached e-mail message.
For most external content, Outlook checks the sender type of the e-mail messages as part of the test for whether to show the contact. E-mail messages from an internal sender are considered safe. Therefore, external content is allowed. Security update 949031 changed this behavior for attached e-mail messages and file system based e-mail messages. With that update applied, the external content is blocked regardless of the sender type. This hotfix, together with the registry value, adds the sender test back. Therefore, if the e-mail message is from an internal sender, the external content is downloaded successfully. The new registry value actually disables the bypassing of the sender type. Therefore, the name of the registry entry is somewhat misleading. By setting the value, you tell Outlook to include the sender type in the test for safety for these kinds of messages.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.