Windows 10 build 18946

Windows 10 build 18946 is an internal build of the Windows 10 May 2020 Update that was accidentally released to users in the Fast Ring on 24 July 2019 alongside the rs_xbox and rs_prerelease compiles of build 18947. This build includes a number of significant changes to the user interface reminiscent of the design changes later found in Windows 10X and Windows 11.

New features
This build notably features a completely redesigned Start menu and a new Control Center design that expands as notifications are received. Both have a similar look to later implementations in Windows 10X and Windows 11, but are disabled by default.

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.