Error message when you use OWA to open a signed e-mail message that is sent as an attachment to an unsigned e-mail message: "The message has a digital signature, but it was not validated"

Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows registry


Consider the following scenario. You open an unsigned e-mail message in Microsoft Outlook Web Access (OWA). This e-mail message includes a signed e-mail message as an attachment. In this scenario, when you open the attached e-mail message, OWA does not validate the message's signature. Additionally, you receive the following error message:
The message has a digital signature, but it was not validated. Attachments will not be included on a reply or forward.
Note You do not experience this problem when both e-mail messages are signed.

Note You do not experience this problem when you open the same e-mail messages in an Outlook client.


This problem occurs if the template that is used to open the signed message does not use the S/MIME control. If the template does not use this control, the template cannot validate the signature.


Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this problem, install this hotfix. After you install this hotfix, you must enable it by adding a CheckEmbeddedSmime registry entry to the
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeWEB\OWA registry subkey. To do this, follow these steps:
  1. Click Start, click Run, type Regedit, and then click
  2. Locate and then click the following registry subkey:
  3. On the Edit menu, point to
    New, and then click DWORD Value.
  4. Type CheckEmbeddedSmime, and then press ENTER.
  5. Right-click CheckEmbeddedSmime, and then click Modify.
  6. In the Edit DWORD Value dialog box, under
    Base, click Decimal.
  7. In the Value data box, type
    1, and then click OK.
  8. Exit Registry Editor.

Hotfix information

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.


Because of file dependencies, this hotfix requires Microsoft Exchange Server 2003 Service Pack 2. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
836993 How to obtain the latest service packs for Exchange Server 2003

Restart requirement

You do not have to restart the computer after you apply this hotfix. However, the following services are restarted automatically when you apply this hotfix:
  • The Microsoft Exchange Information Store service
  • The IIS Admin Service and all dependent services

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) 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 item in Control Panel.
File nameFile versionFile sizeDateTime


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information, click the following article number to view the article in the Microsoft Knowledge Base:
823568 How to configure Exchange Server 2003 OWA to use S/MIME


Article ID: 937851 - Last Review: May 28, 2008 - Revision: 1