Windows auto security update

Hi @Joseph P Atoigue

Yes. If Windows Update is enabled and the KB update is still applicable to the system, Windows may download and reinstall it after it has been uninstalled.

Uninstalling a security update generally removes it temporarily; it does not permanently block Windows Update from offering that update again. This is especially likely with security/quality updates because Windows is designed to keep the system up to date.

If the update is causing a specific problem, you can temporarily pause Windows Updates after uninstalling it while troubleshooting. However, I would not recommend leaving a security update removed for an extended period because it can leave the system exposed to vulnerabilities.

Also keep in mind that Windows updates are cumulative, so a later cumulative update may contain the fixes from the earlier KB. In that situation, Windows may install the newer update rather than the exact same KB.

Microsoft's guidance also notes that not all updates can be uninstalled, and recommends understanding the security risks before removing a security update.

Yep - once Windows Update detects that the device is missing the applicable security update, the update will be reinstalled during a subsequent update scan. There can be a delay before it comes back. Windows Update does not necessarily reinstall an uninstalled update immediately. The device may need to perform another scan, or you may need to select "Check for updates." If the update is still being offered, Windows will normally download and install it again.

There are also some exceptions. If Microsoft has superseded or expired the particular KB, if the KB is no longer applicable to the current Windows build, or if the update has been temporarily paused/blocked by Microsoft, Windows Update may install a newer cumulative update instead of the exact KB that was removed. In the case of Windows 11 cumulative security updates, this is common because a newer cumulative update generally replaces the previous one.

Also, uninstalling a cumulative update is usually temporary from a security perspective. If Windows Update remains enabled, you should expect the vulnerability fixes to return either through the same KB or, more commonly, through a newer cumulative update that contains those fixes.

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hth

Marcin