Unofficially running Windows 11 on an aged PC? The OS soon won't boot - at all - with old CPUs

Here's a warning for those who are running Windows 11 on an ancient PC with a processor that isn't officially supported by Microsoft's operating system - you'll soon be unable to use the OS.

It won't boot up, or at least that's the case according to digging in a preview build of the next big update from Microsoft, Windows 11 24H2, set to debut later this year.

As shared on X (formerly Twitter), Bob Pony unearthed a new stipulation in the preview builds of Windows 11 24H2, first introduced in version 25905 - the requirement for a CPU with the 'POPCNT' instruction.

Apparently 24H2 has various system files requiring this instruction which stands for 'population count' and any vaguely modern CPU will sport this.

However, really old hardware - by which we mean processors older than 15 years, as Windows Central, which noticed the above tweet, observed - does not have POPCNT and so will be unable to even boot Windows 11.

Such ancient CPUs (pre-Windows 7, in fact) aren't supported by Windows 11 anyway, but it's possible to fudge an installation of Microsoft's newest OS on PCs with such chips, should you wish to do so.

For those worried about their PC having an unsupported CPU, even if it isn't all that old - the support cutoff for Windows 11 doesn't include silicon as relatively recent as 7th-gen Intel chips - don't fret. More recent chips, in fact any 'Core i' CPU from Intel (or AMD Barcelona chip onwards) should be just fine with this fresh incorporation of POPCNT.

Should we be surprised Microsoft has made such a move? Hardly, given that these are PCs that shouldn't be running the OS anyway, and the reality is that Windows 11 will be slow and probably flaky as anything on such a system, of course.

Still, if you fall into this decidedly niche category of Windows 11 user, well, you're now on borrowed time, it seems...

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