Windows Update

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This article describes the Windows Update Control Panel. For earlier, web-based versions of Windows Update, see Microsoft Update.

Windows Update interface in Windows Vista

Windows Update is a Control Panel applet found in recent versions of Microsoft Windows that provides updates for the operating system and related components, such as definition updates to the Windows Defender anti-spyware product and Junk Mail filter updates for Windows Mail. Windows Update is also the means to download Windows Ultimate Extras, optional content offered to users of Windows Vista Ultimate.

Microsoft Update is an optional feature in Windows Update that provides updates not only for the operating system, but also certain Microsoft software. It is not enabled by default.

[edit] History

In older versions of Windows, Microsoft Update was a web application. The move away from the web-based paradigm for Windows updates could alleviate the concerns by critics regarding the ability of a web browser to perform trusted update operations on a Windows computer.

A common irritation for Microsoft Update users was that updates requiring a reboot would pop up a dialog box requesting that the user reboot their machine every 10 minutes.^[1] This dialog box would also typically be displayed on top of whatever other applications the user was working with at the time. In Windows Vista, while Windows Update will still require reboots for certain classes of updates, this dialog box was changed to allow the user to select a longer period of time (up to 4 hours) before being prompted again.

Revised Restart dialog box in Windows Vista

The revised dialog box also displays under other applications, instead of on top of them. Windows Update can automatically download and install both Important and Recommended updates. Updating occurs in the background, and flexible options are provided for completing the updating process. If an update requires a restart to complete installation, you can schedule this for a specific time when it won't disrupt your work. You can also postpone a previously scheduled restart until your current work is complete. And when a software update applies to a file in use, Windows Vista can save the application's data, close the application, update the file, and then restart the application.

Windows Update also makes use of Transactional NTFS, a new file system feature in recent versions of Windows, when performing updates to Windows system files. This feature helps Windows recover cleanly in the event of an unexpected shut-down during an update, as the transactioning system will ensure that changes are committed to the file system in an atomic fashion.^[2]