when I log on, or I close my session or when I lock it, it works, I see wallpaper image in background. When I decide to turn off, or restart, I see the shutodnw/restart icon, the message and the countdown, on the "gray" central piece of screen, but not the usual image in the background... wallpaper vanish... it is all white in background. After if I click yes, all white and after I see the usual "boot splash" untill it close or reboot
I had this problem with kubuntu 16.04, I moved today to 16.10 but it's the same...
No idea how to solve it...
sorry for my bad/wrong english