Microsoft's Windows Desktop Update was an optional feature included with Internet Explorer 4 (IE), which introduced several updated shell features to the Windows 95 and Windows NT 4.0 operating systems. These features became part of the standard installation in Windows 98 and later versions.

The Desktop Update included features such as Active Desktop and tight IE4 integration ^{[citation needed]} with the Windows Explorer. It was downloadable as part of IE4 for all versions of Windows 95 except Windows 95 OEM Service Release 2.5 (4.00.950C) which included a standalone version of IE 4.0 (but not slipstreamed) which was automatically installed after the standard Windows 95 set-up. Similarly, the shell update was also made available as part of IE 4.0 for Windows NT 4.0.

While the Windows Desktop Update was officially only an optional user component under Internet Explorer 4.0 releases, and was not formally included in any later version of Internet Explorer (IE5 onwards), large corporations holding Internet Explorer Administration Kit (IEAK) licenses for internal redistribution distribution could generate a version of the IE 5.0x, 5.5 or 6.0 setup which included the update. Also command line parameters can be used to instruct installer of those versions of IE to install Desktop Update.

• Active Desktop - Enables the display of and Internet Explorer renderable web content (e.g. HTML, XML, CDF) and for the first time the displaying of non-BMP image content on the Windows Desktop
• Channels - Push Technology with some similarities to RSS and IE 8's WebSlices. Channels are an XML scripted remote delivery service over http using the .cdf file format. Internet Explorer 4.0 installs of the Desktop Update included localised content and service providers for the main language regions. Installations against IE 5.0 and higher lacked any default subscription content.
• Quick Launch - The quick launch bar first appeared with the Desktop Update, providing a horizontal alternative to Microsoft Office 95/97/2000's vertical launch bar
• Web folders - Explorer windows could display web content and graphics, providing a richer Windows Explorer experience
• Folder Customisation - Individual folders and groups of folders could be customised in appearance using web like formatting constraints
• Ability to show compressed folders in an alternate colour
• Wider array of toolbar customisation in Windows Explorer
• Improved Start menu, including a new 'Favorites' section, more options on the 'Find' menu and menu item drag and drop, edit and delete support

Updates to the Windows Desktop Update were part of IE 4.0 hotfixes and service packs. Later, shell security updates for Windows 95 and Windows NT 4.0 included both the update to the Windows Desktop Update version and the original version. Also sometimes the Windows Desktop Update version and the update to the original version were packaged separately.

The Windows Desktop Update also added the ability to create desk-bands like the quicklaunch bar. It also updated the Windows file manager, explorer.exe (also a shell), to be more modular and extensible.

• Windows Nashville

• http://wallabyweb.com/training/IE4/ Detailed technical documentation of IE4.0, including Windows Desktop Update
• http://www.petri.co.il/install_active_desktop_on_nt_40.htm Detailed HowTo about the installation of the Windows Desktop Update with IE5 and IE6