I guess that the Eject button in the question refers to the Safely Remove Hardware icon or the Eject option. This Safely Remove Hardware icon is on the taskbar. If you don’t see it, please select the Show hidden icons. If you still cannot find the icon, follow the steps below to get it back on taskbar. Right-click the taskbar and then select Taskbar settings. Choose Select which icons appear on the taskbar under the Notification area. Scroll to Windows Explorer: Safely Remove Hardware and Eject Media and turn it on. You can find the Eject option by following the steps I mentioned in the second question.