"Problem Description"
The installed Ubuntu dual system worked fine on the first day. I turned it off, but when I turned it on the next day, I couldn't enter the system. It stayed on the black background startup information refresh screen (mainly by swiping "xxx UID"). 121" and other information). The host computer has an NVIDIA graphics card, so the corresponding graphics card driver is also installed in Ubuntu. If your situation is like mine, you also have an NVIDIA graphics card, and you suddenly cannot enter the system interface normally after restarting. Whether you are ubuntu16, ubuntu18, or ubuntu20, there is basically only one possible reason, and that is that the system kernel file has been accidentally deleted. Updated, causing the system graphics card driver to fail to load when booting, making it impossible to enter the system normally.
"Screenshot of situation"
The interface that stays after booting is this interface, but my screen refresh information is not these. The picture is similar to what I found online.
"Solution"
1. First, connect your computer to the wired network
2. When stuck on the above interface, you can click "Ctrl + Alt + Del" to restart. If your computer is not working, then long press the power button to restart.
3. When the screen starts to refresh the information again, immediately click "Ctrl + Alt + F2" on the keyboard. Be sure to click very quickly until the user logs in to the terminal! But when the user first logs in, don't rush to input, because the information in the background is still refreshing the screen at this time, and you can see the afterimage of the information refreshing. Wait for a while until the user logs in to the terminal and stabilizes, and then enter your Username and password, enter the command terminal system
4. Run the following command to close the graphical interface
sudo service lightdm stop5. Uninstall NVIDIA graphics card driver
sudo apt remove nvidia-driver-470
sudo apt autoremove6. Reinstall the graphics card driver (must be connected to an available wired external network)
sudo apt update
sudo ubuntu-drivers autoinstall7. After the installation is complete, restart the system.
reboot"Finished with flowers"
Not surprisingly, you can now enter the ubuntu system normally. In fact, this kind of booting problem is basically caused by the graphics card driver. As long as your computer has an NVIDIA graphics card and the driver is installed, you will suddenly be unable to enter the Ubuntu interface, so you can just reinstall the graphics card driver without thinking.