XPS15 9560 切換顯卡之後，無法登陸的解決方式

1. Boot as normal and get to login screen

2. press Ctrl + Alt + F1

3. Login with your username and password.

4. type sudo stop lightdm and press enter, stops X11

5. type sudo apt-get purge nvidia* and press enter -clears all nvidia items

6. type sudo apt-get install xserver-xorg-video-nouveau

   and press enter- will install this package or tell you if it is already there.

7. type sudo reboot

this got me back up and running (although no icons in unity launcher - since need correct graphic drivers) check system settings to search for Additional drivers to see if this cab be addressed - although adding wrong drivers may cause the system to be faulty or freeze after login.

XPS15 9560 切換顯卡之後，無法登陸的解決方式