Microsoft has acknowledged that the October security update KB5127648 is creating problems for Windows 11 users attempting to activate Smart App Control on affected systems.
Smart App Control represents a Windows 11 defense mechanism that leverages Microsoft's application intelligence infrastructure and code integrity capabilities. Operating in tandem with Microsoft Defender and SmartScreen, the feature prevents execution of potentially dangerous applications and binary files.
The issue manifests on machines running Windows 11 version 24H2 and newer, where the Smart App Control setting becomes unavailable for adjustment. Microsoft stated in its advisory: "After installing this update, some devices might be unable to turn on Smart App Control in the Windows Security app if it has been turned off. On affected devices, the option to turn on Smart App Control might be grayed out."
The company clarified that "Devices where Smart App Control is already turned on are not affected and remain protected."
While a permanent resolution remains unavailable, Microsoft has provided interim solutions for enterprise administrators managing affected systems. These approaches involve either direct registry modification or deployment of group policy settings.
Registry-Based Workaround
To restore Smart App Control functionality through registry editing, follow these steps:
- Launch Command Prompt by entering cmd in the Search box
- Select Run as Administrator
- Execute the following commands at the prompt, then reboot the device:
reg add "HKLM\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides" /v 2883193997 /t REG_DWORD /d 1 /f reg add "HKLM\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides" /v 2850574478 /t REG_DWORD /d 1 /f
Group Policy Alternative
Enterprise administrators can alternatively deploy group policy to address the issue. Two specific policies must be installed and configured:
- Windows 11, versions 24H2, 25H2, and 26H2 - KB5074105 261015_19222 Feature Preview
- Windows 11, versions 24H2, 25H2, and 26H2 - KB5074105 261015_19221 Feature Preview
These policies are accessible via Computer Configuration > Administrative Templates > {Group Policy name} > Windows 11, version 24H2, 25H2. After installation, administrators must enable both settings and restart the affected machines to implement the changes.
Other Recent Update Issues
This week, Microsoft disclosed additional complications stemming from recent Windows patches. Remote Desktop connections are failing for non-administrator users when the "Administrator protection" security feature is active. The company also resolved a separate issue causing Always On VPN connection failures following the September 2026 security updates.
On Tuesday, Microsoft fixed a bug responsible for black screens, delayed desktop loading, and File Explorer crashes that appeared after Windows 11 updates released since August.