Smart App Control toggle grayed out on some Windows 11 PCs

On certain Windows 11 PCs, the Smart App Control toggle has been grayed out since the installation of the cumulative update KB5127648. Microsoft has acknowledged this bug and is offering temporary workarounds until a permanent fix is available.

How to check if your PC is affected

Users can determine if their machine is affected by checking the status of Smart App Control in Windows Security under App & Browser Control. If the protection is disabled and the reactivation option is grayed out in its settings, the PC is affected. Typing "winver" in the Windows search also gives the installed version and its build number, which is 9711 once KB5127648 is in place.

Devices with Smart App Control already enabled are not affected

Microsoft states that devices where Smart App Control is already enabled are not affected and remain protected. The company lifted this restriction with the cumulative update KB5083769, and then distributed the security update KB5127648 on October 13 with this month's Patch Tuesday. Since its installation, some users can no longer re-enable the protection.

Fix not available for Windows 11 24H2 Family or Pro editions

The fix for Smart App Control will not be distributed to PCs running Windows 11 24H2 Family or Pro. Microsoft is working on a resolution and will provide an update in a future version. This fix will be offered to a PC running Windows 11 24H2 Family or Pro only after its transition to 25H2 or the 26H2 version released at the end of September.

Workarounds using Registry commands or group policies

In the meantime, the two Registry commands are the only way to re-enable Smart App Control on a PC running 24H2 Family or Pro. Microsoft advises backing up the Registry before any manipulation, then provides two commands to execute in an administrator command prompt. After restarting, the Smart App Control toggle is once again usable in Windows Security.

Administrators can use group policies as an alternative

Administrators can replace the Registry commands with two group policies, which Microsoft provides in the form of downloadable .msi packages from the KB5127648 documentation. The publisher asks to install and configure both. With the first, the administrator restores the activation of Smart App Control, and with the second, he has useful logs for troubleshooting.

Microsoft will support 24H2 Enterprise and Education editions until 2027

Microsoft will maintain the Enterprise and Education editions of 24H2 until October 12, 2027. The titles of the two packages refer to KB5074105, an optional January 2026 update that first announced the reactivation of Smart App Control without reinstallation. Members of the Windows Insider program had been testing this feature since November 2025.

Understanding Smart App Control

Smart App Control is a protection that aims to prevent the execution of potentially malicious or untrustworthy applications even before they are launched. It relies on reputation evaluations (signature, origin, suspicious behavior) and can consult cloud analysis services, in addition to Microsoft Defender and SmartScreen.

What is a Windows cumulative update?

A Windows cumulative update (identified by a KB number) groups into a single package security and reliability fixes published up to a certain date, typically during Patch Tuesday. It modifies many components at the same time, which increases the risk of side effects on related functions (Windows Security interface, system policies, feature activation).

How Registry commands work as a workaround

The Registry commands that add values in FeatureManagement\Overrides force "feature flags" states (internal switches used by Windows to enable/disable features). By adding specific DWORD values, a behavior is imposed on the system, even if the interface or a default rule blocks the option. Here, the idea is to lift a software condition that prevents the display or use of the Smart App Control reactivation button in Windows Security. It is a low-level action: it works around the problem rather than fixing the cause, which explains the recommendation to back up the Registry. After restarting, Windows re-reads these indicators and the interface can become consistent with the expected state.