All problems started after I update my Ubuntu 16.04 LTS and wifi driver has gone. I spent so many times to solve this problem. Actually there is no problem. There is driver more than one. After I update Ubuntu I realized, update that I did, installs an other driver of broadcam. That new wifi driver installation caused the wifi problem. As the result, all you need this command : sudo apt purge bcmwl-kernel-source That command will remove broadcam installation which had been installed by update. Lastly... Reboot your system : sudo reboot That's it. Now, Everything could be okay. This method solved to my problem. I hope, it will also be useful for you.