Windows 10 build 18946

Windows 10 build 18946 is an internal build of the Windows 10 May 2020 Update, which was accidentally flighted to all Insiders in the Fast Ring on 24 July 2019. It is currently the only available build to be compiled under the  branch.

Breaking the known Insider Program release routine, Microsoft also managed to accidentally release the rs_prerelease and rs_xbox compiles of build 18947 before simultaneously pulling all three releases after publishing the AMD64 variant of this build within five minutes. The UX routine was also broken in this build, bringing with it a number of significant changes to the user interface, of which are reminiscent to the design changes found in Windows 10X and Windows 11.

New features

 * A fully redesigned Start menu.
 * A new Control Center design that expands as notifications are received.

Enabling the new features

 * To enable the new Start menu, use the mach2 tool, run an elevated command prompt session and type in.
 * To enable the new Control Center design, open the Registry Editor and navigate to, then create a DWORD value named   with a value of 1.