Ubuntu Unity 15.04: Black Screen at Login

Question

I have already researched solutions to fix this: After logging in, there's a black screen and my cursor, nothing else! in Ubuntu 12.10 But I have more questions that need to be answered. Knowing how anal the interwebz gets about duplicate posts, I would just comment on the existing threads, but hte reputation gate wont allow me.

I also ran into this problem a few months ago on Ubuntu Gnome where the screen would go black before I could enter my password. The same this is happening here in Unity after running a system update and then rebooting. I installed Unity on my laptop a few weeks ago and used the Nvidia proprietary driver as indicated in the Software and Updates window under Additional Drivers. Using that I have no problems. Only when I add the xorg-edgers ppa to my repositories and then executing a system update as notified does this problem occur. I used the same ppa in Ubuntu Gnome which generated the same problem. This time in Unity I didn't even install anything form the repository so I don't know why this happens. I could be making assumptions based on the correlation I see between adding the ppa, running updates, and then rebooting with a black screen before login.

QUESTION:
How do I get access to the terminal to start trouble shooting the black screen nonsense if I can't get a login screen? Lately my beset solution is to clone the drive before this nonsense happens and image it back if it does break.

Answer 1

In the Grub menu press the button in the bottom, which brings kernel launch options and add "nomodeset" there (dont remember what button it was).

Then it will most probably boot you into a desktop.

Then if your laptop is an optimus one use the following instructions in this answer: Nvidia Driver and Heating Problem

Answer 2

1. Open a text-only virtual console by using the keyboard shortcut Ctrl+Alt+F3.

2. At the login: prompt type your username and press Enter.

3. At the Password: prompt type your user password and press Enter.

4. Now you are logged in to a text-only virtual console, and you can run terminal commands from the console. To reboot the system from the console run the command: sudo shutdown -r now. Press the keyboard shortcut Ctrl+Alt+F7 to exit from the virtual console. In Ubuntu 17.10 and later press the keyboard shortcut Ctrl+Alt+F2 to exit from the virtual console.

5. Sometimes if you just run the command: sudo reboot from the console, your computer will boot to your normal login screen when it reboots. This does not work every time or in all situations, but you may want to try it once anyway. Also this way of getting to your normal login screen is a workaround that does not fix anything, so you will still need to do something else to fix the black screen problem.

There are some models of Nvidia graphics cards for which the proprietary graphics driver cannot be successfully installed except if the ppa:xorg-edgers/ppa is added to the software sources. ppa:xorg-edgers/ppa is also known to cause many boot failure problems, and I have read a lot of bad advice recommending adding ppa:xorg-edgers/ppa to the software sources in situations in which it is not appropriate.