Microsoft accidentally pushed out an internal Windows 10 build to Insiders this morning, making quite some waves on an otherwise slow Wednesday night. This untested canary build revealed a new look of the Start menu, however, this build was pushed out to all rings, including the Slow and Release Preview rings that expect to receive tested, stable builds.

Build 18947 (branch 20H1) was compiled just a day ago, which means it wasn't internally tested yet. Microsoft has now pulled it back and explained how to revert back to a stable build. In its statement, the Windows maker said that it internally tests and validates each build before releasing them externally to the Insider community and that "a configuration change allowed this build to release to multiple rings simultaneously, including external rings."

Microsoft added that it has now "implemented additional changes to help prevent from this happening in the future."

We apologize for any troubles this may have caused for affected Insiders and appreciate your assistance in bringing this to our attention so we could make the necessary changes as quickly as possible.

It is recommended, especially for those on the Slow and Release Preview rings, to roll back to their previous build within the next 10 days as they won't be able to do so afterwards.Microsoft detailed:

We’d like to share information with you regarding build 18947 as released to Windows Insider audiences earlier today. We’ll cover what happened and how to revert your device to your desired state.

Who: Windows Insiders who installed build 18947

What: Insiders who installed this build, especially those in the Slow and Release Preview rings, will need to use the rollback function to restore to their previous build

Why: An internal preview build was unintentionally released to a broader audience than expected.

When: Affected users generally have ten days (10) after installing build 18947 to complete the rollback process before losing the ability to do so. If you have Storage Sense enabled, this time window may be reduced. We encourage affected users to complete this action as soon as possible to ensure they’re able to roll back successfully.

Here is how to roll back to your previous Windows 10 build

Before proceeding, confirm whether you actually havethis canary build running on your machine. Go to Start> type WINVER> select WINVER (Run command). You will see a window showing the build number that is installed on your device.

If it is version 18947, here is how to roll back:

Click StartOpen Settings (the sprocket icon)Select Update & SecuritySelect RecoveryUnder “Go back to the previous versions of Windows 10” select Get StartedComplete the on-screen steps as follows:For “Why are you going back”, select “For Another Reason”Under “Tell us more” enter 18947Click Next On the “Check for updates?” screen, select “No, thanks”There will be two more screens with information to review. Please read each screen, clicking Next to continue.You will see one final screen. Select Go back to earlier build to initiate the rollback process.

These steps will restore your device to the previous, hopefully stable, build. More details here.

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