Windows 11 just got its latest update, but Microsoft has put it on hold following the discovery of a bug that’s seriously bad news.

This is the KB5039302 update, which is an optional download for Windows 11 22H2 and 23H2, so it’s still in preview, ahead of its release as the cumulative update for July 2024 next month.

The showstopper of a bug puts affected PCs into what’s known as ‘reboot hell’ whereby the PC keeps failing to start, rebooting, failing again, then rebooting, and so on ad infinitum – well, until the user intervenes and tries to initiative a recovery. (Or in some cases, unplugs their PC out of frustration, no doubt – never do this if you can at all avoid it, we should add, as cutting power at the wrong time can be bad news for your system drive, as it could corrupt files potentially).

What’s the root cause here? Well, it appears to have something to do with PCs using virtual machines (running another OS inside the current operating system, essentially).

Neowin noticed that in its release health dashboard, where this gremlin has been flagged up, Microsoft tells us: “This issue is more likely to affect devices utilizing virtual machines tools and nested virtualization features, such as CloudPC, DevBox, Azure Virtual Desktop. We are investigating to determine the precise conditions under which this issue can trigger.”

While that investigation is taking place, Microsoft has paused this update, so it won’t be offered to Windows 11 home users or businesses.


Unhappy millennial male employee work online on laptop at home office frustrated by gadget error or mistake. Angry young Caucasian man stressed with computer operational problem or breakdown.

(Image credit: Shutterstock / fizkes)

Analysis: Room for doubt

Clearly, given that having a PC trapped in a reboot loop is a dire scenario, it’s a good idea that Microsoft has pulled this update until the firm can work out what’s really going on here. This is an optional update anyway, so it’s not like KB5039302 is crucial, or even finished – which is why this flaw is present, no doubt.

Although you’d really have hoped Microsoft would have picked up on such a calamitous bug before the final preview release of the update – but at least it’s being fixed now. This also goes to illustrate why it’s always a risk to download an optional update for Windows 11 – we’d recommend steering clear of these in case there is a last-minute showstopper, just like this glitch.

Granted, as Microsoft observes: “Users of Windows Home edition are less likely to experience this issue, as virtualization is less common in home environments.”

Even so, some Windows 11 Home users will use virtualization features, no doubt, and Microsoft isn’t 100% clear about the bug not affecting other PCs either. The language used is that the problem is “more likely” to hit PCs using virtual machines in some way, leaving room for doubt that it could affect other systems too. This is likely why the update has been retracted, for now, we’d wager.

The crucial thing is that Microsoft fixes this one up, or at least pushes the feature or code that’s caused the problem aside, before the full release of the July 2024 cumulative update, clearly enough.

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