Yesterday, we reported on Microsoft's release faux pas which resulted in a Windows 10 preview build accidentally being leaked. This was a Canary ring release meant for internal testing and showcased parts of the new Start menu. Windows Insider chief Dona Sarkar said the company would look into the matter.
Microsoft has responded officially to the leak, explaining how the accidental release happened. Perhaps more importantly, the company offered instructions on how Insiders can roll back to a previous build.
The accidental leak is Windows 10 Preview Build 18947. Insiders on Slow and Fast Rings were able to download it, and probably did so believing it was an official release. While it may seem interesting on paper to have a super-early Win10 version with a new Start menu, most Insiders probably don't want this build and are now stuck on it.
Microsoft's Jason Howard wrote a Microsoft Answers post discussing the leak. He says a configuration change caused the build to release to the Inside. That issue has now been solved.
As for rolling back, Howard says Insiders should check if they are indeed on the accidental build 18947 release. This can be done by heading to Settings > System > About. Users not on the build should still check in with Windows Update to ensure the unwanted release is not pending.
If it is pending, users are advised to pause the update for seven days, in which time it will be cancelled.
For users who did download build 18947, Howard says a roll back is easy. They can head to Settings > Update & security > Recovery > Go back to previous version of Windows 10. Instructions on screen will detail how to complete the roll back.
For users who think they want to hang on to this update, the only way to receive another update afterwards is to be on the Fast Ring. That's because Slow Ring and Release Preview branches are on Windows 10 19H2 and 19H1 respectively and cannot update to Windows 10 20H1 builds.