How to fix a frozen Ubuntu session
Are you having issues with your Ubuntu session freezing while you use it? Can you still type on the keyboard and use your mouse, but nothing is responsive? If so, we can help! Follow along with this guide as we show you how to fix a frozen Ubuntu session!
Resetting the login screen
The best way to fix a frozen Ubuntu session is to force the login screen program to reset. By forcing the login screen to reset itself, you’ll make the Ubuntu session log out, fixing the problem. To be clear, forcing the Ubuntu login screen to reset will cause your session to exit immediately, and you will not be able to save any work in progress.
Resetting the Ubuntu login manager is difficult because there isn’t just one version of Ubuntu. There is Xubuntu, Lubuntu, Kubuntu, Ubuntu Budgie, Ubuntu Mate, and others. Each of these versions of Ubuntu all has their login managers.
To reset your Ubuntu login screen, start by pressing Ctrl + Alt + F2 through F6 on the keyboard. By pressing this keyboard combination, you will be presented with the TTY screen. TTY is the emergency console and can be accessed at any time while using Ubuntu.
In the TTY screen, you will see “login.” Enter your user account in the login box by typing it out on the keyboard. Then, press the Enter key to submit your user.
After submitting your user, the TTY screen will ask you to enter the password associated with it. Do so. Do not worry if you see no password feedback. Just type it out on the keyboard and press Enter when done typing to submit it.
Once you’ve logged into the TTY screen, you will have access to a terminal session, just like when you open up a terminal window on the Linux desktop. From here, follow the command-line instructions below to learn how to reset your login screen for Ubuntu, Lubuntu, Xubuntu, Kubuntu, Ubuntu Budgie, Ubuntu Mate, and more.
Ubuntu
The default release of Ubuntu Linux uses the Gnome desktop manager as it’s the login screen. If you’d like to reset it to fix your frozen session, you’ll need to use the systemctl restart command on the gdm.service file.
sudo systemctl restart gdm.service
Upon entering the command above, your Ubuntu session should automatically log out, and you’ll be back at the login screen. From here, select your user and log back in!
Kubuntu
Kubuntu is built on KDE, which means that it uses the SDDM login manager. To reset your Kubuntu session, you will need to make the systemctl restart command reboot the sddm.service file.
sudo systemctl restart sddm.service
Once you enter the command above, your Kubuntu session will be forced to log out. After logging out, simply click on your Linux user and log back into the session!
Xubuntu
Xubuntu is XFCE4, and because of this, it uses the LightDM login manager. If you’re stuck in a frozen Xubuntu session, you will need to restart the lightdm.service file using the systemctl restart command below.
sudo systemctl restart lightdm.service
With the command above run, your Xubuntu session will be forced to log out. After logging out, you’ll be back at your LightDM login screen. From here, just select your user and log back in!
Lubuntu
Lubuntu uses LXQt, which is similar to Kubuntu’s KDE. As it is using software similar to KDE, Lubuntu uses the SDDM login manager. If your Lubuntu session is frozen, you’ll be able to fix it by restarting the sddm.service file with the systemctl restart command.
sudo systemctl restart sddm.service
When the command above finishes restarting, your Lubuntu session will be forced to close and log out. From here, select your user and log back into Lubuntu!
Ubuntu Budgie
Ubuntu Budgie uses the Budgie desktop environment. Budgie is built upon the Gnome Shell desktop, but it uses the LightDM login manager, rather than Gnome DM (gdm). So, if you have a frozen Ubuntu Budgie session, you will need to restart the lightdm.service file with systemctl restart in a terminal.
sudo systemctl restart lightdm.service
After restarting the LightDM login manager, your Budgie session will be forced to log out. At that point, you can quickly log back into Ubuntu Budgie and get back to work!
Ubuntu Mate
Ubuntu Mate uses the Mate desktop; a fork of the old Gnome 2 desktop environment. Since it is a fork of an old version, it does not use Gnome DM (GDM). Instead, Ubuntu Mate uses LightDM to manage the login screen.
To reset the Ubuntu Mate login screen in the event of a frozen session, you will need to restart the lightdm.service file with the systemctl restart command. Using the command below, reset the LightDM login manager.
sudo systemctl restart lightdm.service
As soon as you restart the LightDM login manager, your Mate desktop session will close, and you’ll be returned to the login screen. From here, click on your user and log back in.
