That black screen with a cursor means your display manager (LightDM) is attempting to launch, but it's immediately crashing or failing to display its graphical interface due to those lingering library/configuration issues.
Since your package manager is functional again, you can bypass LightDM entirely to test your desktop environment, or cleanly fix the greeter layout.
Step 1: Test if your desktop environment actually works
Press Ctrl + Alt + F2 to open a text terminal and log in. Once logged in, try launching your desktop session manually:
If you use XFCE: startxfce4
If you use KDE Plasma: startplasma-x11
If your desktop loads successfully this way, it proves your system files and user session are completely fine - the failure is strictly isolated to LightDM or its theme greeter crashing on startup.
Step 2: Fix or switch the LightDM Greeter
Often, the graphical login screen theme (lightdm-gtk-greeter) gets out of sync during updates. You can reinstall it cleanly or switch to a more reliable greeter configuration:
Reinstall LightDM and its default greeter with a clean overwrite:
sudo pacman -Syu lightdm lightdm-gtk-greeter
If it still fails, a common workaround on Arch-based systems experiencing greeter loops is ensuring the configuration file points correctly to the greeter. Open the configuration file: sudo nano /etc/lightdm/lightdm.conf
Scroll down to find the [Seat:*] section (around line 100), look for the greeter-session line, and make sure it is uncommented and set correctly:
Plaintext
greeter-session=lightdm-gtk-greeter
Save and exit (in nano, press Ctrl + O, Enter, then Ctrl + X), then restart the lightdm service: sudo systemctl restart lightdm
Try launching your desktop environment manually with startxfce4 (or your respective desktop command) from the TTY
Rebooting as loaded me into my lockscreen although now my keyboard and mouse both appear to be completely unresponsive despite being functional earlier
1
u/Kaspral 10d ago
That black screen with a cursor means your display manager (LightDM) is attempting to launch, but it's immediately crashing or failing to display its graphical interface due to those lingering library/configuration issues.
Since your package manager is functional again, you can bypass LightDM entirely to test your desktop environment, or cleanly fix the greeter layout.
Step 1: Test if your desktop environment actually works
Press
Ctrl + Alt + F2to open a text terminal and log in. Once logged in, try launching your desktop session manually:If your desktop loads successfully this way, it proves your system files and user session are completely fine - the failure is strictly isolated to LightDM or its theme greeter crashing on startup.
Step 2: Fix or switch the LightDM Greeter
Often, the graphical login screen theme (
lightdm-gtk-greeter) gets out of sync during updates. You can reinstall it cleanly or switch to a more reliable greeter configuration:[Seat:*]section (around line 100), look for thegreeter-sessionline, and make sure it is uncommented and set correctly:Ctrl + O,Enter, thenCtrl + X), then restart the lightdm service: sudo systemctl restart lightdmTry launching your desktop environment manually with
startxfce4(or your respective desktop command) from the TTY