Editing Windows Update (section)

{{Short description|Software update distribution service for Microsoft Windows}}
{{Use dmy dates|date=October 2018}}

{{Infobox software
| name = Windows Update
| logo = Windows Update Icon 2022.png
| logo_size = 60px
| screenshot = Windows Update screenshot.png
| screenshot_size = 300px
| caption = Windows Update on [[Windows 11]]
| developer = [[Microsoft]]
| other_names = Microsoft Update
| service_name = Windows Update
| included with = {{plainlist|
* [[Windows Vista]] and later
* [[Windows Server 2008]] and later
  }}
| operating system = {{Plainlist|
* [[Windows 9x]] family
* [[Windows NT]] family
}}
| genre = [[Network service]]
| website = {{URL|1=https://support.microsoft.com/en-us/windows/windows-update-faq-8a903416-6f45-0718-f5c7-375e92dddeb2|2=support.microsoft.com/en-us/windows/windows-update-faq}}
}}
'''Windows Update''' is a [[Microsoft]] service for the [[Windows 9x]] and [[Windows NT]] families of the [[Microsoft Windows]] operating system, which automates downloading and installing Microsoft Windows [[software update]]s over the [[Internet]]. The service delivers software updates for Windows, as well as the various Microsoft [[Antivirus software|antivirus products]], including [[Windows Defender]] and [[Microsoft Security Essentials]]. Since its inception, Microsoft has introduced two extensions of the service: '''Microsoft Update''' and '''Windows Update for Business'''. The former expands the core service to include other Microsoft products, such as [[Microsoft Office]] and [[Microsoft Expression Studio]]. The latter is available to business editions of [[Windows 10]] and permits postponing updates or receiving updates only after they have undergone rigorous testing.

As the service has evolved over the years, so has its client software. For a decade, the primary client component of the service was the Windows Update [[web app]] that could only be run on [[Internet Explorer]]. Starting with [[Windows Vista]], the primary client component became Windows Update Agent, an integral component of the operating system.

The service provides several kinds of updates. ''Security updates'' or ''critical updates'' mitigate vulnerabilities and [[exploit (computer security)|security exploits]] in Microsoft Windows. ''Cumulative updates'' are updates that bundle multiple updates, both new and previously released updates. Cumulative updates were introduced with Windows 10 and only some been backported to [[Windows 7]] and [[Windows 8.1]]. Windows 11 24H2 also introduced checkpoint cumulative updates<ref>{{Cite web |title=Introducing Windows 11 checkpoint cumulative updates |url=https://techcommunity.microsoft.com/t5/windows-it-pro-blog/introducing-windows-11-checkpoint-cumulative-updates/ba-p/4182552 |access-date=2024-10-16 |website=TECHCOMMUNITY.MICROSOFT.COM |language=en}}</ref> and updates with Hotpatch capability in the name, where some of the updates no longer require a reboot. <ref>{{Cite web |last=robinharwood |date=2023-10-10 |title=Hotpatch for Windows Server Azure Edition |url=https://learn.microsoft.com/en-us/windows-server/get-started/hotpatch |access-date=2024-10-16 |website=learn.microsoft.com |language=en-us}}</ref><ref>{{Cite web |last=Zorz |first=Zeljka |date=2024-09-23 |title=Windows Server 2025 gets hotpatching option, without reboots |url=https://www.helpnetsecurity.com/2024/09/23/windows-server-2025-hotpatching/ |access-date=2024-10-16 |website=Help Net Security |language=en-US}}</ref>

Microsoft routinely releases updates on the second Tuesday of each month (known as the [[Patch Tuesday]] B updates) but can provide them whenever a new update is urgently required to prevent a newly discovered or prevalent exploit, so-called out-of-band updates.<ref>{{Cite web |title=May 23, 2024—KB5039705 (OS Build 17763.5830) Out-of-band - Microsoft Support |url=https://support.microsoft.com/en-us/topic/may-23-2024-kb5039705-os-build-17763-5830-out-of-band-2285667a-13a3-4fd9-98a0-e980eb996aac |access-date=2024-10-16 |website=support.microsoft.com}}</ref> System administrators can configure Windows Update to install critical updates for Microsoft Windows automatically, so long as the computer has an Internet connection.

In Windows 10 and [[Windows 11]], the use of Windows Update is mandatory; however, the software agreement states that users may stop receiving updates on their device by disconnecting their device from the Internet.<ref>{{Cite web |title=Microsoft License Terms |url=https://www.microsoft.com/en-us/Useterms/Retail/Windows/10/UseTerms_Retail_Windows_10_English.htm |access-date=March 30, 2020 |website=www.microsoft.com |at=Section 13b |archive-date=1 August 2015 |archive-url=https://web.archive.org/web/20150801002634/https://www.microsoft.com/en-us/Useterms/Retail/Windows/10/UseTerms_Retail_Windows_10_English.htm |url-status=live }}</ref><ref>{{Cite web |title=Microsoft Software License Terms |url=https://www.microsoft.com/en-us/UseTerms/Retail/Windows/11/UseTerms_Retail_Windows_11_English.htm |access-date=2022-07-20 |website=www.microsoft.com |quote="Canada. You may stop receiving updates on your device by turning off Internet access. If and when you re-connect to the Internet, the software will resume checking for and installing updates." |archive-date=1 May 2023 |archive-url=https://web.archive.org/web/20230501155625/https://www.microsoft.com/en-us/UseTerms/Retail/Windows/11/UseTerms_Retail_Windows_11_English.htm |url-status=live }}</ref>

There also exist C and D updates,<ref>{{Cite web |last=Hoffman |first=Chris |date=2018-12-12 |title=Now Windows 10 Has C, B, and D Updates. What is Microsoft Smoking? |url=https://www.howtogeek.com/398226/now-windows-10-has-c-b-and-d-updates.-what-is-microsoft-smoking/ |access-date=2024-10-16 |website=How-To Geek |language=en}}</ref> that users enroll in when they click the update button.<ref>{{Cite web |last=Fortin |first=Michael |last2= |first2= |date=2018-12-10 |title=Windows monthly security and quality updates overview |url=https://blogs.windows.com/windowsexperience/2018/12/10/windows-monthly-security-and-quality-updates-overview/ |access-date=2024-10-16 |website=Windows Experience Blog |language=en-US}}</ref>