this seems to be a big problem people are having with the newer versions of ubuntu so i thought i would share a fix to a broken feature they advertise falsely in their "edit connection" section.
sudo apt-get install macchanger
sudo apt-get install gedit
make shell script with content below and put this in /home/username/Desktop/init.d/
#!/bin/bash
pre-start script
macchanger -m 00
E:AD:BE:EF:0f wlan0
/sbin/wpa_supplicant -u -s -O /var/run/wpa_supplicant &
python -c 'import dbus; print
dbus.SystemBus().call_blocking("fi.epitest.hostap.WPASupplicant",
"/fi/epitest/hostap/WPASupplicant", "fi.epitest.hostap.WPASupplicant",
"addInterface", "sa{sv}", ("wlan0", {"driver":"wext"}))'
end script
post-stop script
macchanger -p wlan0
end script
seems to be the solution until ubuntu fixes this bug. sharing and fixing bugs is a huge part of what makes linux the best operating system evar!!