ubuntu18.04强制关机后进不了桌面low-graphics mode

出现：

the system is running in low-graphics mode

缘由：

卸载搜狗拼音误删了文件，而后强制关机(应该桌面设置出现了问题)

解决：

rm -rf /var/lib/lightdm/.cache/*
rm -rf /var/cache/lightdm/*
rm -rf /tmp/.X11-unix
mv /var/lib/lightdm/.Xauthority /var/lib/lightdm/.Xauthority_bk
mv /var/lib/lightdm/.dbus/session-bus/ /var/lib/lightdm/.dbus/session-bus_bk/

dpkg-reconfigure lightdm
# 选择gdm3，而后启动gdm3
service gdm start