If you stuck in the login screen and can’t load the Ubuntu desktop, follow those steps.

  1. when you on the login screen, press ctrl + shift + alt + f1. A black screen appeared? No? Just the login page? So try ctrl + shift + alt + f2. Still the login screen? try ctrl + shift + alt + f3. If the login screen still showing? Try to use another external keyboard.

  2. a black screen appeared? ok, type your username then ENTER and type your password then ENTER.

  3. type ping 8.8.8.8 then ENTER to ensure you have a good Internet connection. If you have Internet access follow the steps. If you PC not connected to the Internet, try to use Ethernet cable (wired connection).

  4. uninstall/remove all desktop environments that does not let you log into the desktop itself

If you have ubuntu budgie desktop, uninstall it like this.

sudo apt-get purge --auto-remove ubuntu-budgie-desktop

If your desktop environment if XFCE desktop, uninstall it by this command.

sudo apt-get purge --auto-remove xfce

To uninstall LXDE desktop, use this command.

sudo apt-get purge --auto-remove lxde

If you have any other desktop environment, search online to know the name of the package of it, then use this command to uninstall it from your laptop / computer.

sudo apt-get purge --auto-remove desktop-environment-package-name
  1. update & upgrade all your packages on your system.
sudo apt-get update

then

sudo apt-get upgrade -y

or just use this command sudo apt-get update && sudo apt-get upgrade -y.

(if there is any updates or upgrades downloaded/installed, type “reboot” then ENTER to restart your computer)

  1. After that run those commands

note : if you rebooted / restarted your computer, press ctrl + shift + alt + f1 to open the command terminal. And follow the steps below.

sudo apt-get purge fglrx lightdm

then

sudo apt-get install lightdm ubuntu-desktop

Now, we uninstalled all desktop environments, then updated the packages, then installed one desktop environment (ubuntu-desktop) on clean operating system.

I hope it works for you! IF NOT WORKED, SHARE IT WITH YOUR FRIENDS TO HELP THEM.