1.安装gnome
sudo apt-get install gnome-session-flashback
2.卸载unity7.5
sudo apt purge unity8 ubuntu-system-settings
3.卸载unity7.5
sudo apt purge unity 7.5 ubuntu-system-settings
4.清除残留
sudo apt autoremove
5.桌面优化
原文链接：https://www.f2er.com/ubuntu/352417.html略
