Start menu completely non-functional

The July preview update broke the Start menu completely. Clicking the Start button did nothing. Pressing the Windows key did nothing. The most prominent UI element in Windows — the one with the operating system’s name on it — simply stopped responding. Microsoft deployed an emergency server-side fix within 24 hours, which is unusually fast for them, perhaps because “the Start button doesn’t work” is the one bug even a Microsoft executive would notice during their morning coffee.