Windows 11 Smart App Control grayed out after KB5127648: fixed for 25H2/26H2 by KB5127936
After the October 2026 security update KB5127648, some PCs could not turn Smart App Control back on (option grayed out). Microsoft fixed it for Windows 11 25H2 and 26H2 with KB5127936 (preview dated Oct 28; updates on/after Oct 27). 24H2 still uses the documented workaround path.