Editing Windows Update (section)

===Windows Update Agent===
[[File:Windows Update Restart Vista.png|thumb|Revised restart [[dialog box]] in [[Windows Vista]]|alt=]]
Starting with [[Windows Vista]] and [[Windows Server 2008]], ''Windows Update Agent'' replaces both the Windows Update web app and the Automatic Updates client.<ref>{{Cite web|url=https://support.microsoft.com/en-us/help/949104/how-to-update-the-windows-update-agent-to-the-latest-version|title=How to update the Windows Update Agent to the latest version|date=6 June 2017|website=Support|publisher=[[Microsoft]]|access-date=22 November 2018|archive-date=4 September 2020|archive-url=https://web.archive.org/web/20200904183049/https://support.microsoft.com/en-us/help/949104/how-to-update-the-windows-update-agent-to-the-latest-version|url-status=live}}</ref><ref>{{Cite web|url=https://technet.microsoft.com/en-us/library/cc735627(v=ws.10).aspx|title=Windows Update Agent|date=13 December 2007|website=[[Microsoft TechNet|TechNet]]|publisher=[[Microsoft]]|access-date=22 November 2018|archive-date=14 January 2018|archive-url=https://web.archive.org/web/20180114073712/https://technet.microsoft.com/en-us/library/cc735627(v=ws.10).aspx|url-status=live}}</ref> It is in charge of downloading and installing software update from Windows Update, as well as the on-premises servers of [[Windows Server Update Services|Windows Server Updates Services]] or [[System Center Configuration Manager]].<ref>{{Cite web|url=https://technet.microsoft.com/en-us/library/bb932139.aspx|title=How to Install the Windows Update Agent on Client Computers|date=2007|website=[[Microsoft TechNet|TechNet]]|publisher=[[Microsoft]]|access-date=22 November 2018|archive-date=11 October 2018|archive-url=https://web.archive.org/web/20181011053744/https://technet.microsoft.com/en-us/library/bb932139.aspx|url-status=live}}</ref><ref>{{Cite web|url=http://searchwindowsserver.techtarget.com/definition/Microsoft-Windows-Update-Agent|title=Microsoft Windows Update Agent|last=Rouse|first=Margaret|date=May 2014|website=TechTarget|access-date=22 November 2018|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127080207/https://searchwindowsserver.techtarget.com/definition/Microsoft-Windows-Update-Agent|url-status=live}}</ref>

Windows Update Agent can be managed through a [[Control Panel (Windows)|Control Panel]] applet, as well as [[Group Policy]], [[Microsoft Intune]] and [[Windows PowerShell]]. It can also be set to automatically download and install both ''important'' and ''recommended'' updates. In prior versions of Windows, such updates were only available through the Windows Update website. Additionally, Windows Update in Windows Vista supports downloading [[Windows Ultimate Extras]], optional software for Windows Vista Ultimate Edition.

Unlike Automatic Updates in Windows XP, Windows Update Agent in Windows Vista and Windows 7 allows the user to postpone the mandatory restart (required for the update process to complete) for up to four hours. The revised dialog box that prompts for the restart appears under other windows, instead of on top of them. However, standard user accounts only have 15 minutes to respond to this dialog box. This was changed with [[Windows 8]]: Users have 3 days (72 hours) before the computer reboots automatically after installing automatic updates that require a reboot. Windows 8 also consolidates the restart requests for non-critical updates into just one per month. Additionally, the login screen notifies them of the restart requirements.<ref>{{cite web |last=Savov |first=Vlad |url=https://www.theverge.com/2011/11/15/2563251/windows-8-update-restart-consolidation |title=Windows 8 auto-update will consolidate restarts into one per month, give you three days to do it |website=[[The Verge]] |publisher=[[Vox Media]] |date=15 November 2011 |access-date=22 November 2018 |archive-date=29 August 2021 |archive-url=https://web.archive.org/web/20210829051505/https://www.theverge.com/2011/11/15/2563251/windows-8-update-restart-consolidation |url-status=live }}</ref>

Windows Update Agent makes use of the [[Transactional NTFS]] feature introduced with Windows Vista to apply updates to Windows system files. This feature helps Windows recover cleanly in the event of an unexpected failure, as file changes are committed [[atomicity (database systems)|atomically]].<ref name="filecab">{{cite web |title=NTFS Beta Chat Transcript (July 12, 2006) |url=https://blogs.technet.microsoft.com/filecab/2006/09/20/ntfs-beta-chat-transcript-july-12-2006/ |date=12 July 2006 |work=Storage at Microsoft |publisher=Microsoft |access-date=22 November 2018 |archive-date=20 April 2019 |archive-url=https://web.archive.org/web/20190420233542/https://blogs.technet.microsoft.com/filecab/2006/09/20/ntfs-beta-chat-transcript-july-12-2006/ |url-status=live }}</ref>

Since [[Windows 8]], the Windows Update is able to offers device firmware updates, for example [[UEFI]].

[[Windows 10]] contains major changes to Windows Update Agent operations; it no longer allows the manual, selective installation of updates. All updates, regardless of type (this includes hardware drivers), are downloaded and installed automatically, and users are only given the option to choose whether their system would reboot automatically to install updates when the system is inactive or be notified to schedule a reboot.<ref name=cnet-scheduleupdate>{{cite web|title=Windows 10 lets you schedule Windows Update restarts|url=http://www.cnet.com/how-to/windows-10-lets-you-schedule-windows-update-restarts/|website=CNET|access-date=4 August 2015|archive-date=19 February 2015|archive-url=https://web.archive.org/web/20150219130153/http://www.cnet.com/how-to/windows-10-lets-you-schedule-windows-update-restarts/|url-status=live}}</ref><ref name=crn-updates>{{cite web|title=Did Microsoft Just Backtrack On Forced Updates For Windows 10?|url=http://www.crn.com/news/applications-os/300077576/did-microsoft-just-backtrack-on-forced-updates-for-windows-10.htm|website=CRN.com|date=27 July 2015|access-date=4 August 2015|archive-date=28 July 2015|archive-url=https://web.archive.org/web/20150728071222/http://www.crn.com/news/applications-os/300077576/did-microsoft-just-backtrack-on-forced-updates-for-windows-10.htm|url-status=live}}</ref> Microsoft offers a diagnostic tool that can be used to hide troublesome device drivers and prevent them from being reinstalled, but only after they had already been installed and then uninstalled without rebooting the system.<ref name=iw-nvidiadriver>{{cite web|title=On the road to Windows 10: Nvidia driver tests KB 3073930 patch blocker|url=http://www.infoworld.com/article/2952996/microsoft-windows/on-the-road-to-windows-10-botched-nvidia-driver-tests-kb-3073930-patch-blocker.html|website=InfoWorld|date=27 July 2015|access-date=31 July 2015|archive-date=20 June 2017|archive-url=https://web.archive.org/web/20170620044549/http://www.infoworld.com/article/2952996/microsoft-windows/on-the-road-to-windows-10-botched-nvidia-driver-tests-kb-3073930-patch-blocker.html|url-status=live}}</ref><ref name=iw-3073930>{{cite web|title=On the road to Windows 10: Problems with forced updates and KB 3073930|url=http://www.infoworld.com/article/2951214/microsoft-windows/on-the-road-to-windows-10-problems-with-forced-updates-and-kb-3073930.html|website=InfoWorld|date=22 July 2015|access-date=31 July 2015|archive-date=20 June 2017|archive-url=https://web.archive.org/web/20170620052143/http://www.infoworld.com/article/2951214/microsoft-windows/on-the-road-to-windows-10-problems-with-forced-updates-and-kb-3073930.html|url-status=live}}</ref>

Windows Update Agent on Windows 10 supports [[peer-to-peer]] distribution of updates; by default, systems' [[bandwidth (computing)|bandwidth]] is used to distribute previously downloaded updates to other users, in combination with Microsoft servers. Users may optionally change Windows Update to only perform peer-to-peer updates within their [[local area network]].<ref name=pcw-peertopeer>{{cite web|title=How to stop Windows 10 from using your PC's bandwidth to update strangers' systems|url=http://www.pcworld.com/article/2955491/windows/how-to-stop-windows-10-from-using-your-pcs-bandwidth-to-update-strangers-systems.html|website=PC World|publisher=IDG|access-date=4 August 2015|archive-date=5 August 2015|archive-url=https://web.archive.org/web/20150805145115/http://www.pcworld.com/article/2955491/windows/how-to-stop-windows-10-from-using-your-pcs-bandwidth-to-update-strangers-systems.html|url-status=live}}</ref>

Windows 10 also introduced cumulative updates. For example, if Microsoft released updates KB00001 in July, KB00002 in August, and KB00003 in September, Microsoft would release cumulative update KB00004, which packs KB00001, KB00002, and KB00003 together. Installing KB00004 will also install KB00001, KB00002 and KB00003, mitigating the need for multiple restarts and reducing the number of downloads needed. KB00004 may also include other fixes with their own KB number that were not separately released.<ref>{{Cite web |url=https://support.microsoft.com/en-us/help/4133604/ |title=User can't log on to a POP/IMAP account by using NTLM authentication in Exchange Server 2013 |quote=To resolve this issue, install Cumulative Update 21 |access-date=24 March 2020 |archive-date=10 February 2021 |archive-url=https://web.archive.org/web/20210210014628/https://support.microsoft.com/en-us/topic/user-can-t-log-on-to-a-pop-imap-account-by-using-ntlm-authentication-in-exchange-server-2013-22c7f67d-87a5-75d2-501e-82cdc21f94b9 |url-status=live }}</ref> A disadvantage of cumulative updates is that downloading and installing updates that fix individual problems is no longer possible. KB stands for knowledge base, as in [[Microsoft Knowledge Base]].