Microsoft ships two kinds of Windows update each month: the mandatory security release on the second Tuesday, and an optional “preview” a couple of weeks later that carries the next month’s non-security changes early for anyone who wants them. June’s preview, KB5039302, was a reminder of why the word is there. On some Windows 11 PCs it broke restarting — the machine would loop and never come back — and on others the taskbar disappeared, leaving a desktop with no Start button. Microsoft pulled the update within days and has now fixed both problems in July’s security update, KB5040442.
Who was hit
The restart loop affected Windows 11 versions 23H2 and 22H2, and almost only machines using virtualisation — Cloud PC, DevBox, Azure Virtual Desktop, or virtual-machine tools such as Hyper-V and VMware on a desktop. Home edition PCs were largely spared because they rarely run those tools. The missing-taskbar bug hit N editions of Windows (the European variants sold without Media Player) and any system where the Media Features package had been switched off; the taskbar depends, oddly, on a media component that the update assumed was present.
What to do
- Open Settings → Windows Update and install everything offered. KB5040442 arrives as the “2024-07 Cumulative Update” and takes the build to 22631.3880 (23H2) or 22621.3880 (22H2).
- If a PC is stuck in the restart loop, boot into the recovery environment (hold Shift while clicking Restart, or power-cycle three times), choose Uninstall Updates, remove the latest quality update, then install July’s.
- To check your build, press Win+R, type
winver, and read the number.
The lesson about previews
Preview updates are Microsoft’s public beta for the following month’s changes. On a home laptop they are harmless enough; on a PC that earns money — a freelancer’s workstation, a bank branch, a university lab — there is no reason to take them. Windows does not install them unless you click Download and install under optional updates, so the fix is simply not to. Security updates, on the other hand, should be installed the day they appear; KB5040442 also closes 142 vulnerabilities, four of them already being exploited.
Source: BleepingComputer, via Prothom Alo.
