Windows 11's Smart App Control switch is grayed out after you turn it off; two registry values from Microsoft turn it back on

Turning Smart App Control off is one click. Turning it back on is where this bug bites: Microsoft says “some devices might be unable to turn on Smart App Control in the Windows Security app if it has been turned off,” with the toggle sitting gray and unclickable.

“Devices where Smart App Control is already turned on are not affected.” If yours is on, leave it alone.

Your Windows 11 version	What to do
26H2 or 25H2 with the October 27, 2026 update (KB5127936) or later	Install it; the issue is resolved
24H2, or any version before that update	Use Microsoft’s registry workaround below

The workaround, as Microsoft gives it: open Command Prompt as administrator and run two lines.

reg add "HKLM\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides" /v 2883193997 /t REG_DWORD /d 1 /f
reg add "HKLM\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides" /v 2850574478 /t REG_DWORD /d 1 /f

Then restart, and the switch should be live again. Microsoft also lists a Group Policy route for managed machines.

Feature flags like these two numbered values are how Microsoft turns features on and off across millions of PCs, and a bug in that plumbing shows up as a setting that’s simply unavailable. The registry lines are Microsoft’s own override, not a community hack, which is why they’re safe to paste as written.

Microsoft’s notes don’t say what the two numbered values do on their own, or whether 24H2 will get the update fix.