So Microsoft is simply bringing back a Start button that will be enabled by default in Windows 8.1 and works across the desktop mode and Start Screen.

If the Aero Peek or Show desktop button is not working or missing in Taskbar in Windows 11/10 then this post shows ways on how you can fix the problem.

Click the toggle button that says: Use peek to preview the desktop…. For the second method, which many will prefer, right-click the Show Desktop button to reveal its context menu, shown in Figure C.