Microsoft support policy for the customization of Outlook Web Access for Exchange

Applies to: Exchange Server 2010 EnterpriseExchange Server 2010 StandardMicrosoft Exchange Server 2003 Enterprise Edition More


This article describes the Microsoft Customer Service and Support (CSS) policy for the customization of scripts, graphics, and other files in the following products:
  • Microsoft Outlook Web App (OWA) for Microsoft Exchange Server 2010
  • Microsoft Outlook Web Access (OWA) for Microsoft Exchange Server 2007, Microsoft Exchange Server 2003, Microsoft Exchange 2000 Server, and Microsoft Exchange Server 5.5

More Information

First, this article explains which kinds of OWA customizations are not supported. Then, it provides information about which customizations are supported and where you can find the documentation for those scenarios.

Unsupported Customizations

You may want to change OWA features or the user interface to better suit the needs or your organization. Many OWA source files can be edited or changed on the server. Therefore, it is possible to modify the default functionality of OWA. However, Microsoft CSS only supports customizing OWA in ways that are documented as part of Microsoft's Exchange or OWA documentation on the Microsoft Developer Network (MSDN) or TechNet websites. Any other customizations are not supported or recommended by Microsoft. All OWA source files should be treated as regular source code files unless there is Microsoft documentation that describes how the files should be customized.

Microsoft CSS cannot help you with any undocumented customizations. If you want to customize OWA, the following limitations and considerations apply:
  • Microsoft CSS does not provide assistance with customizing OWA components.
  • If you contact Microsoft CSS about an OWA issue for a server on which OWA is customized, you may have to replace the customized files with the original versions of the files and verify that you can reproduce the issue by using the original versions of the files. If the issue occurs only with the customized versions of the files, and you cannot reproduce the issue with the original versions of the files, Microsoft CSS cannot help you troubleshoot the issue.
  • If you install an Exchange service pack, rollup, or hotfix that updates OWA files, any customized files may be overwritten. If you do not want to lose the customizations that you created, create a backup of the customized files, and then restore the files after you install the service pack, rollup, or hotfix. You should review any Exchange release notes before you install service packs, hotfixes, and hotfix rollups to find instructions about how to handle overwrites to customizations.

The following OWA feature areas are common requests for customization, but are not supported by Microsoft CSS:
  • Custom user authentication logic and the default user interface.
  • The custom logoff button.
  • Modifying the user interface on any page other than the logon page.
  • Using an ISAPI filter to modify OWA. You can use an ISAPI filter to monitor OWA.
  • Using the full OWA user interface in a custom iFrame HTML tag. Instead, you can consider whether using an OWA web part in an iFrame tag may suit your needs. For more information, visit the following Microsoft TechNet website:

Peer-to-Peer Assistance

Microsoft public forums provide peer-to-peer support for the Exchange developer community. To view the Exchange Development forum, visit the following Microsoft website:

Supported Customizations

Support for customizing OWA varies, depending on the version of Microsoft Exchange that is used. However, all versions of OWA allow you to create custom web forms for custom item types. Web forms must be registered for custom message classes. Customizing the built-in item types is not supported.

The following is a summary of the documented and supported features for customizing OWA.
Exchange Server 2010
Exchange Server 2010 allows you to customize the following aspects of OWA:
  • Add custom forms
  • Integrate other applications through navigation pane links
  • Add items to the New drop-down menu
  • Add items to the right-click (context) menu
  • Integrate with other Instant Messaging server products
To view documentation about how to customize OWA in Exchange 2010, visit the following Microsoft TechNet website:

Exchange Server 2007
Exchange 2007 allows you to create custom forms for OWA and customize some elements of the user interface. To view documentation about how to customize OWA in Exchange 2007, visit the following Microsoft TechNet websites:

Exchange Server 2003 and Exchange 2000 Server
The Exchange 2000 Server and Exchange Server 2003 versions of OWA are composed of two main components: templates and controls. Templates are served from a binary Internet Server API (ISAPI) extension that communicates with the Exchange store. Controls are referenced by the templates and are located in the Program Files\Exchsrvr\Exchweb folder. Controls are made up of script or HTML files, such as JScript files (.js), HTML Component files (.htc), cascading style sheet files (.css), XSL transform files (.xsl), and graphics files.

To view documentation about how to create web forms with OWA 2003, visit the following Microsoft websites:

The Exchange 2000 Server SDK provides documentation about how to create web forms with OWA 2000. To download this SDK, visit the following Microsoft website:

  For more information about Exchange 2000, click the following article number to view the article in the Microsoft Knowledge Base:  
321832 How to change the Outlook Web Access logon page