Just updated to Win11 24H2 and it has killed Windows Hello!

This should be fixed in the July 2025 patch (update build > 26100.4351, along with any associated Microsoft Store UWP app updates).

If the issue still occurs (e.g., a crash in BioEnrollmentHost.exe), the problem may be with a video codec that was included in previous versions of Windows but now needs to be installed or provided.

How new do the cameras need to be to support this enhanced sign-in security you are speaking about here?

Im assuming a laptop that i bought this year in January would be considered fairly new since it supports the latest Windows Hello parameters.

And if the upgrade route youre mentioning would work, then mine would be working as this is what i did, without changing anything about the facial data and hence it should have been preserved. Yet it just didnt function properly.

A lot of work to be done by microsoft to fix this.

I didnt see that error anywhere btw.

New devices (Secured Core / CoPilot+ PCs) use "Enhanced Sign-in Security", which requires drivers and hardware that enable encryption/authentication at a low hardware level.

The error I mentioned is from the crash in the MFPLAT.DLL (Media Foundation Platform DLL).

The problem can be "fixed" from either Microsoft's side (add or handle codecs/encoding/resolutions as they did in Windows 10-11 23H2), or from the camera manufacturer's driver side (use or transcode to a 24H2 supported codec/resolution).

We opened a support case with Microsoft and paid the $500 fee, and still haven't heard anything in months. MS is unable or unwilling to fix this issue it appears. This issue affects our hybrid joined machines, they can't use Windows Hello Biometric options like face or fingerprint to login. We can't use our Yubico FIDO2 security keys to sign-in on Windows hybrid joined machines either after this update. We've basically been forced to eliminate the hybrid joined machines and convert them to Microsoft Entra joined instead, which doesn't have this issue. This has been a major hassle for us. We've essentially given up on Microsoft fixing this and have moved on.

I appreciate that disabling Fast Start has helped some others, but as I have said previously, I tried it, and it didn't help me. In fact, since I was forced to reinstall Windows, Fast Start has been disabled.
I have just installed update KB5055523, with the hope Microsoft have finally fixed the issue ... they have not. It even appears that they have simply disabled facial biometrics on affected machines, as I tried the troubleshooter before going for the final desperate step of contacting MS Support. It deleted the biometric device, and after several reboots, it has not reappeared.
So ... I went through the painful process of asking MS support ...I gave them control of my machine for a couple of hours(!). They pretty much ignored all I told them, and went through everything I had already tried. I waited patiently, with the hope they would conclude it was an actual problem, and they would escalate to someone that would take it seriously, and had the power to escalate further ... the support guy got to the same point I did, and without warning, downloaded the Windows 11 ISO, and opened it ...I had to shout STOP (well, type), and explained that last time I tried this, I ended up with a BSoD and had to reinstall Windows, losing all my applications (but thankfully keeping all my data) .. he typed into Quick Assist that an in-place install would only repair and update ...I was just typing that I knew the theory, but it caused problems last time ...then Quick Assist promptly terminated, and I went back to the support portal (https://support.microsoft.com/home/contact), to find that he had closed my request!!!!! What a complete waste of time. showing the incredible lack of professionalism in Microsoft. I expect the closed case will show on his KPIs as a job well done!

I found temporality disabling fast restart solved my issues with Windows Hello.