● Covered by 2 sources · 3 reportsMedium impact1 negative2 neutral
Microsoft October Windows Update Breaks Smart App Control for Some Users
Key points
- KB5127648 update disables Smart App Control toggle.
- Affects Windows 11, version 24H2 and later.
- Devices with Smart App Control already on are protected.
- Microsoft provided registry and Group Policy workarounds.
- October Patch Tuesday update rolled out on October 13.
- Smart App Control was added to Windows 11 in 2022.
- Microsoft fixed the issue with the KB5127936 preview update.
- The fix was released on October 28, 2026.
Smart App Control Issue Identified
Microsoft has confirmed that its October KB5127648 security update for Windows 11 can prevent users from enabling Smart App Control. This issue specifically affects devices running Windows 11, version 24H2 and later, where the option to turn on Smart App Control appears grayed out in the Windows Security app.
Feature Description and Impact
Smart App Control is a security feature in Windows 11 designed to block potentially harmful applications and binaries. It operates by utilizing Microsoft's app intelligence services and code integrity features, working in conjunction with Microsoft Defender and SmartScreen. Devices that already had Smart App Control enabled before the update are not affected and continue to receive protection.
Temporary Workarounds Provided
While a permanent fix is not yet available, Microsoft has issued temporary workarounds for IT administrators. These mitigation steps involve either modifying the system registry or installing and configuring specific Group Policies. The registry modification requires entering two commands in an elevated command prompt and then restarting the device.
For enterprise-managed devices, IT administrators can install and configure two Group Policies (KB5074105 261015_19222 Feature Preview and KB5074105 261015_19221 Feature Preview) found under Computer Configuration > Administrative Templates. After enabling these settings and restarting the affected devices, Smart App Control can be turned on.
Updates
- Microsoft fixed the issue with the KB5127936 preview update.
- The fix was released on October 28, 2026.
- October Patch Tuesday update rolled out on October 13.
- Smart App Control was added to Windows 11 in 2022.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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How outlets covered it
Microsoft has released a fix for an issue preventing some Windows 11 users from activating the Smart App Control security feature after installing the October 2026 KB5127648 update. The problem caused the Smart App Control option to be grayed out, but devices with the feature already enabled remained protected.
Microsoft's October Patch Tuesday update for Windows 11 introduced a bug that disables Smart App Control, a security feature designed to block malicious applications. Users are unable to re-enable the feature if it is turned off, leaving systems vulnerable to new threats. Microsoft is working on a fix, but a temporary registry workaround is available.
Microsoft's October KB5127648 security update for Windows 11 prevents some users from enabling Smart App Control, a feature that blocks potentially harmful applications. Devices with Smart App Control already active are unaffected, but newly affected devices cannot toggle the feature on, leaving them without this protection.