Smart App Control uses Microsoft's code integrity features and app intelligence services, and it works alongside SmartScreen and Microsoft Defender to block potentially harmful apps or binaries. As the company explained when it acknowledged the issue last month, the Smart App Control option is grayed out and cannot be toggled on affected devices running Windows 11 24H2 and later. "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," Microsoft said in the KB5127648 advisory. "Devices where Smart App Control is already turned on are not affected and remain protected." On Wednesday, the company confirmed that the issue has been fixed for users who installed this month's KB5127936 preview update. "This issue was resolved by Windows updates released October 28, 2026 [..] and later.
