Windows 11 22H2 update failing with error 0x800f0806, here are potential fixes
As reports had suggested, Microsoft released Windows 11 version 22H2 to the general availability channel on September 20. You can read all about the new exciting stuff in these articles here. A few days before that, some users received the 2022 feature update early with new devices. The machines were shipping with build 22621.521 (KB5017321) which was indeed the 22H2 update as confirmed later by Microsoft.
Since release, many, however, are reporting of problems and issues when trying to update to Windows 11 22H2. According to these reports, the update is failing with an error code "0x800f0806". This is apparently happening when trying to do an in-place upgrade via Windows Update in Settings due to some compatibility issue or something similar. A clean install though is seemingly working fine.
Thankfully, a Reddit user by the name rap1021 has found a solution to the issue. Apparently, manually downloading and installing the update seems to bypass this problem caused by trying to do an upgrade via Windows Update. To do so, simply head over to Microsoft's Update Catalog website and download the update.
Other known solutions like running the "sfc /scannow" via Command Prompt, or resetting the Windows Update mechanism don't appear to be working either according to the same user, and manually downloading the update is seemingly the best bet.
Another user, CusiDawgs, on the same thread says the latest version of Windows 11 Installation Assistant also resolves the problem. You can download it from Microsoft's official website here.
Edit: Looks like one of our Neowin members "kiddingguy" had also noticed the issue and came up with the workaround. So here's a shoutout to them!