my wifi was not working at all after installing
16.04/rc yesterday on my Nexus 5 (I didn't wipe the device, coming from
15.04/rc). Wifi switch button was always ON after any reboot, but it didn't show any networks or connect to known networks.
I was able to make wifi work by running
nmcli r wifi on in terminal, since
nmcli g stated, that wifi is just disabled (while UI stated, that wifi is ON). Until next reboot, wifi seems to be working and respect UI switch state changes. After reboot, it doesn't work again.
From outside view it seems that on reboot it somehow wrongly decide if wifi is either ON or OFF and it just states ON and switch button doesn't work. I would assume, that if I had disabled wifi before reboot, it should be still disabled after reboot...
Hope this helps somebody else too.