GoKawiilMicrosoft patches Smart App Control bug introduced by KB5127648 update
Microsoft has fixed an issue that left the Smart App Control security feature grayed out and unable to be turned on for some Windows 11 24H2+ devices after installing the October 2026 KB5127648 update. The company says the fix is included in the KB5127936 preview update released October 28, 2026, and devices that already had Smart App Control enabled were never affected. Microsoft also published a registry-edit workaround for enterprise admins who prefer to wait for next month's cumulative update rather than install the preview patch.
GoKawiil's interpretation of the reporting above, not reported fact.
The bug temporarily blocked some users from enabling a key anti-malware defense layer, which could have left affected machines more exposed until remediated. Microsoft's offering of both an early preview patch and a manual registry workaround suggests it is trying to give IT administrators flexibility in managing update risk across enterprise fleets. The episode highlights the recurring tension between shipping security updates quickly and avoiding regressions that undermine the very protections being delivered.
- KB5127648 broke the ability to enable Smart App Control on some Windows 11 24H2+ devices.
- The fix shipped in the KB5127936 preview update released October 28, 2026.
- Admins not ready to deploy the preview can use a registry-edit workaround until the next Patch Tuesday update.
Source: bleepingcomputer.com, 2026-11-02
Published there as: “Microsoft fixes Smart App Control broken by October Windows update”
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