Microsoft: October Windows update may break Smart App Control

Microsoft says the KB5127648 Windows 11 security update may leave Smart App Control grayed out and impossible to enable on Windows 11 24H2 and later. Devices where the feature is already on remain protected. No fix is available yet, but Microsoft shared registry and Group Policy workarounds.

• Issue affects Windows 11 24H2, 25H2 and 26H2 after KB5127648
• Smart App Control option is grayed out and cannot be toggled
• Devices with the feature already enabled stay protected
• Workarounds: registry edits or two Group Policies