Microsoft Fixes Smart App Control Bug in Windows 11
Microsoft has resolved a known issue affecting Windows 11 users who were unable to activate the Smart App Control security feature following an October security update.
Radwan AbdulhadiEditor and technology writer
Overview of the Smart App Control Issue
Microsoft has resolved a known issue that prevented some users from activating the Smart App Control security feature after installing the October 2026 KB5127648 Windows 11 security update, according to a report by <a href="https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-smart-app-control-broken-by-october-windows-update/">BleepingComputer</a>.
Smart App Control uses Microsoft's code integrity features and app intelligence services, working alongside SmartScreen and Microsoft Defender to block potentially harmful apps or binaries on supported systems.
Impact on Windows 11 Devices
As the company explained when it acknowledged the issue, the Smart App Control option became grayed out and could not be toggled on affected devices running Windows 11 version 24H2 and later.
Detailed information regarding the affected versions and behavior can be found directly within the <a href="https://support.microsoft.com/en-us/servicing/os/windows-11/2026/10/kb5127648-windows-11-24h2-25h2-26h2-security-update">KB5127648 advisory</a> published by the software giant.
Microsoft stated in the advisory that after installing the update, some devices might be unable to turn on Smart App Control in the Windows Security app if it had been turned off. However, the company noted that devices where Smart App Control was already turned on were not affected and remained protected.
Resolution and Preview Updates
Microsoft confirmed that the issue has been fixed for users who installed the KB5127936 preview update, which brought a range of changes and improvements to the operating system.
Further details regarding the contents of this release are outlined in the <a href="https://www.bleepingcomputer.com/news/microsoft/windows-11-kb5127936-update-released-with-41-changes-and-fixes/">KB5127936 preview update</a> coverage, detailing multiple fixes introduced alongside the security patch.
The company noted in a service alert sent to IT administrators that the issue was resolved by Windows updates released on or after October 28, 2026, recommending that users install the latest available security updates.
Workarounds for IT Administrators
Microsoft also shared a temporary fix for administrators who prefer not to deploy the preview update on enterprise-managed devices and intend to wait for the upcoming Patch Tuesday cumulative updates.
Administrators can review health dashboards and administrative guidance <a href="https://admin.cloud.microsoft/Adminportal/Home?source=applauncher#/windowsreleasehealth/:/issue/WI1509826">in a service alert sent to IT administrators</a>, which provides comprehensive tracking of the mitigation status.
The workaround requires editing the registry on affected Windows 11 devices via Command Prompt to restore the ability to toggle Smart App Control. Alternatively, administrators can apply specific Group Policy settings under Computer Configuration to enforce Smart App Control functionality and enable troubleshooting logs.
Additional Fixes in Recent Releases
Alongside the resolution for Smart App Control, the recent preview updates address several other persistent problems reported by users following previous system patches.
Notably, the updates include fixes that <a href="https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-remote-desktop-failures-caused-by-recent-windows-updates/">resolves Remote Desktop failures</a> triggered when the "Administrator protection" security feature is enabled.
Furthermore, the release <a href="https://www.bleepingcomputer.com/news/microsoft/microsoft-finally-fixes-vpn-issues-caused-by-september-updates/">finally fixes Always On VPN issues</a> that had been caused by the cumulative updates deployed in September 2026.
Sources
- BleepingComputerMicrosoft fixes Smart App Control broken by October Windows update
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