Yesterday, Windows 10 Preview build 14986 rolled out with a lot of improvements. But many users were having issues even downloading the update. Insiders were informed that Microsoft had been made aware of the bug and that it was working on a fix.
Seems like the team was right on top of the bug because now a solution has been issued for the error 80240031. Thankfully, the fix is as simple as running a troubleshooter from Microsoft that will restore your PC to a stable state. The statement explains:
This tool performs a number of actions which will get you back to a clean update state. You will need an active internet connection to download this tool and to re-download build 14986 as needed. Once the tool has completed, return to the Settings panel and re-scan for updates. 14986 should download as expected.
The team also notes that anyone that edited their registry keys as a workaround the error will be causing more issues in the future if they don't revert them back to the original values.
If you've had issues downloading the latest Insider preview build for the Fast Ring, download the troubleshooter program on the support page and let us know if it works for you.