1. sudo passwd root 2. sudo gedit /etc/gdm/gdm.conf change AllowRoot＝false => true Ctrl+Q 3. 重新開機 4. 如此就可以使用root登入了。
![sudo apt-get update 出錯 Updating from such a repository can‘t be done securely, and is therefore[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)