(1) 打开终端，输入sudo service network-manager stop (2) sudo rm /var/lib/NetworkManager/NetworkManager.state (3) sudo service network-manager start ---到这应该就能看到按钮了，如果还看不到接着执行下面的 (4) sudo vim /etc/NetWorkManager/NetworkManager.conf，将其中的managed=false改为managed=true (5) sudo service network-manager restart
