What really happened is the Tablet mode has switched on for no apparent reason.

It puts me into panic mode where I thought my Windows 10 is frozen in a weird state, without investigating further I often restart my machine. Unable to access my Desktop and all the Taskbar’s icon are missing. At first, I wasn’t sure what to do, since the Start menu is the only thing showing on the entire screen. But personally, I’ve encountered this a number of times, where for no obvious reasons it would switch to Tablet mode on a dedicated Desktop machine. Perhaps, when Windows 10 is fully released issues like this will no longer occur. Sometimes Windows get confused between when to enable/disable Tablet mode To check which mode you are on you can open the notification tray and check the status from the bottom of the screen. Windows 10 suppose to know and be able to detect when your machine is in Tablet mode and when it is in Desktop mode. This is to support the bridging and gap between the new Start menu and the, now old, Start menu from Windows 8.1. In Windows 10, there is a new and improved feature to allow the user to seamless switch from Tablet mode and Desktop mode.

Wallpaper disappears windows 10