Main Menu does not appear cannot be accessed

From the latest firmware 2.02.32, that IS the main menu now. It’s called Grid. Open Services by clicking the Bell icon, find the videos app and select it add add it to the main menu via the options key. It’s all explained in the link below

http://community.wd.com/t5/WD-TV-Live-Streaming/GRID-UI-totally-indecipherable/m-p/785317/highlight/true#M32663

If you want to go back to the old style main menu you have to rollback to the previous firmware.