"Outlook cannot display this view. Unknown Error" error message is generated in Outlook client and Event ID 9667 is logged on an Exchange Server 2003 server


Microsoft Exchange Server 2003 has a quota limitation for named properties. When many X-headers are promoted to named properties and the quota limitation is reached, you may receive the following error message in Microsoft Office Outlook:
Outlook cannot display this view. Unknown Error.
Additionally, you find the following error message in the Application log:


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 the problem described in this article. 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.


Before you install this hotfix for Exchange Server 2003, you must install Exchange Server 2003 Service Pack 2 (SP2).

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.
The following services are restarted automatically when you apply this hotfix:
  • Microsoft Exchange Information Store service
  • Microsoft Search service
  • Internet Information Services (IIS) Admin Service
  • All dependent services

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

Installation information

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
After you apply this fix, you may follow these steps to set a registry entry to control the promotion of X-headers for named properties:
  1. Click Start, click Run , type regedit , and then click OK.
  2. Locate and then click the following registry subkey:
  3. On the Edit menu, point to New , and then click DWORD Value.
  4. Type GenerateNamedProperties, and then press ENTER.
  5. Quit Registry Editor.
A 0 value of the GenerateNamedProperties attribute will not generate new named properties.
The default behavior is true when this registry entry is not found.

More Information

For more information about named properties and X-Headers, visit the following Microsoft Web site:

Article ID: 972077 - Last Review: Mar 16, 2010 - Revision: 1