Microsoft has a pretty embarrassing problem on its hands, and it is affecting a number of users in the Windows Insider program. Microsoft has several “rings” that it uses to distribute test builds of Windows 10 to Insiders. Slow, Fast, and Skip Ahead builds escalate in their instability, but offer users a way to test out upcoming features ahead of the general public.
However, an error on Microsoft's part caused an internal build of Windows 10 20H1 -- Build 18947 -- to push to all Windows 10 development rings. This error is problematic on multiple fronts. Those on the Slow ring are used to relatively stable test builds, and with this being an internal build, it's definitely more prone to show-stopping bugs. According to Zac Bowden, who first reported on the slip-up, Build 18947 is a canary build and it hasn't even been tested by Microsoft.
In a Twitter post, Bowden wrote:
For context, your usual Insider Preview build is about 5-7 days old before it rolls out to Insiders in the Fast ring. 18947 isn't even a day old an it's rolling out in all rings. So be cautious if you're running 32-bit Windows with the Insider Program enabled.
Upon the initial report of the unintended rollout, it was implied that only 32-bit machines were receiving the internal build. However, subsequent reports from users revealed that those with 64-bit systems are also receiving Build 18947.
So, for anyone that is currently serving as a Windows Insider, now might be a good time to pause updates through the Settings app; that is if your system hasn't already been updated to this problematic build of Windows 10 20H1. For its part, Microsoft's head of the Windows Insider Program, Dona Sarkar, simply replied on Twitter that "We're looking into it."