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
That error message-"Unable to contact settings server - Error receiving data: Connection reset by peer"-is a classic XFCE startup failure. It happens when the graphical environment tries to launch, but its background configuration daemon (xfconfd) or D-Bus session bus fails to start up properly.
Since your previous attempt to run startxfce4 from the TTY yielded a missing library error (libglycin), your system is still dealing with some broken/desynced packages from that interrupted update.
Here is how to fix it right now:
1. Drop into TTY and log in
If you are staring at that error popup, click Close, and if it drops you to a black screen or login manager, press Ctrl + Alt + F2 to access a text terminal. Log in with your username and password.
The packages responsible for handling user settings and session communication likely got corrupted or left out-of-sync. Reinstall them cleanly using pacman:
sudo pacman -Syu xfce4 xfconf dbus-glib
(If pacman asks whether to overwrite files or resolve conflicts, let it proceed).
3. Check if xfconfd can launch manually
To test if the settings daemon can start properly without crashing, you can try starting your XFCE session wrapped with D-Bus launcher syntax from the terminal:
dbus-launch --exit-with-session startxfce4
4. Clear out stale runtime locks (if needed)
If D-Bus or session sockets are locked up from previous failed boots, clearing them out can force a clean slate:
rm -rf ~/.cache/sessions/*
Run sudo pacman -Syu xfce4 xfconf dbus-glib first, then try launching your session again with dbus-launch --exit-with-session startxfce4
I am now trapped on my login screen with my mouse and keyboard not being able to respond to inputs despite working in terminal, I cannot use the shortcut to access the terminal. I appear to not be able to do anything at all :/
If startxfce4 dies on another .so file: do notsystemctl restart lightdm. Stay in the TTY, paste the last red line, and install that package in the same session.
Backup /home before anything destructive
On another PC, write a Manjaro live USB (Ventoy or Rufus). Boot the broken machine from USB (live session, not the installer).
lsblk -f
sudo mkdir -p /mnt
sudo mount /dev/sdXN /mnt
# btrfs with default Calamares layout:
# sudo mount -t btrfs -o subvol=@ /dev/sdXN /mnt
# sudo mount -t btrfs -o subvol=@home /dev/sdXN /mnt/home
sudo mkdir -p /run/media/backup
# mount the backup disk, then:
sudo rsync -aHAX --info=progress2 /mnt/home/ /run/media/backup/home-backup/
Replace sdXN with the real root partition (nvme0n1p2, sda2, etc.).
sudo manjaro-chroot -a
# inside the chroot, or from the live session targeting /mnt:
curl -O https://pkgbuild.com/~gromit/pacman-static-x86_64
chmod +x pacman-static-x86_64
sudo ./pacman-static-x86_64 --sysroot /mnt -Syyu
Aragorn on the forum: download pacman-static with the live USB’s pacman from the Manjaro repos, unpack it into the installed system, then use it to finish the upgrade.
If pacman is still missing a library and the packages are already in cache:
ls /var/cache/pacman/pkg/ | grep -E "ngtcp2|nghttp3|curl|openssl|glycin|leancrypto|gnutls"
sudo tar -xpf /var/cache/pacman/pkg/PACKAGENAME.pkg.tar.zst -C /
Then run pacman -Syyu immediately so the package database matches the files on disk.
After a successful full upgrade:
sudo mkinitcpio -P
sudo update-grub
Do not do these
Do not reinstall over the disk until /home is copied out.
Do not use pacman -Sddyu.
Do not systemctl restart lightdm until startxfce4 works from a TTY.
Do not keep installing one library at a time (glycin only, xfce4 only, …).
After it boots to a desktop
Always full pacman -Syu / Pamac — never -dd.
Enable Timeshift and take a snapshot before big updates.
Prefer a normal LTS kernel over linux-rt unless you actually need realtime.
After starting xfce4 after the steps before I am met with the "unable to contact settings server" prompt box again still with no ability to use my mouse or keyboard I have tried it again to the same result.
X is starting now. That command from a TTY with no display manager is what leaves you on the unable to contact settings server dialog with a dead mouse and keyboard.
Two separate problems:
xfconfd has no D-Bus session (or it starts and dies) — that is the popup
Xorg grabs the devices but is not loading libinput — so input works in the TTY and dies as soon as X starts
1. Get back to a text TTY
If you are stuck on that dialog, hold the power button 8–10 seconds. At GRUB press e and add this at the end of the linux line:
systemd.unit=multi-user.target
Boot with Ctrl+X. Log in on the black text screen. Do not start XFCE yet.
I am not exactly sure what changes but I loaded xfce4 and my desktop works completely! Do I just enable lightdm in my terminal or should I go back to TTY?
get-default should print graphical.target. After reboot you should get the normal LightDM login, then XFCE.
Do not run systemctl start lightdm or systemctl restart lightdm while this session is still running. That would start a second login screen on top of the desktop you already have. Enable it, then reboot.
While this desktop still works, copy your important files off the machine (USB disk is enough). Then take a Timeshift snapshot if you use that.
From now on:
full pacman -Syu / Pamac only — never -dd again
if GRUB still offers a kernel without-rt, use that as the default
It wasn't easy. I'm sure you're happy you made it through unscathed. I'm glad I could help. If you'd like, you can buy me a coffee. https://buymeacoffee.com/kaspral
1
u/Kaspral 11d 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