Depending on the setup dunst was unable to connect to the X server or the wayland compositor in use. In case of X make sure that X is running and that the DISPLAY environment variable is correctly set. For a wayland based setup the WAYLAND_DISPLAY environment variable needs to be set to a valid value.
If dunst should be automatically started by dbus or via the systemd service, it is important to know that both don’t inherit environment variables set by a shell.
There are various ways to make them aware if they’re missing.
For a X based setup either use systemctl --user import-environment DISPLAY or add a call to /etc/X11/xinit/xinitrc.d/50-systemd-user.sh in xinitrc.
With a wayland setup systemctl --user import-environment WAYLAND_DISPLAY would be used instead.
If systemd knows about those environment variables, dbus should too.
But if there are still issues with the dbus session then dbus-update-activation-environment --systemd --all can be used to update the current session.
Dunst cannot connect to your session bus at all. The session bus might not even exist.
Please check all these conditions:
DBUS_SESSION_BUS_ADDRESS is really setAnother notification daemon is already running, which is listening for notifications. Usually this is another daemon, which got autostarted or is dunst itself.
Usually, dunst also prints the PID of this process, which will give you more possibilities to investigate. Maybe you want to simply kill this PID and then start dunst.
The connection to the dbus daemon failed or another process is using the notification address. Make sure that the DBUS_SESSION_BUS_ADDRESS environment variable is set and if not you should consult your distributions documentation on how to properly setup dbus.
Additionally, verify that the output of
gdbus call --session --dest org.freedesktop.DBus --object-path /org/freedesktop/Dbus --method org.freedesktop.DBus.ListNames
Does not contain org.freedesktop.Notifications. If it does it means that another notification daemon is already running.
Since the 1.2 version release, an option max_icon_size was introduced to scale down icons to a certain size. By default this option is set to 0 (it doesn’t scale down icons), to change this behaviour you need to set this option in the global section of the config file. For reference, check out the dunstrc config example file.
D-Bus does not know which notification daemon it should start. So it decides arbitrarily which one to use.
You have to link the D-Bus service file of your preferred notification daemon into your home folder.
To change the notification daemon back to the default, open up a shell and execute these two commands:
mkdir -p "${XDG_DATA_HOME:-$HOME/.local/share}/dbus-1/services"
ln -sfT \
"/usr/share/dbus-1/services/${SERVICE:-org.freedesktop.Notifications}.service" \
"${XDG_DATA_HOME:-$HOME/.local/share}/dbus-1/services/org.freedesktop.Notifications.service"
If you want to switch back to dunst again, first define SERVICE=org.knopwob.dunst and re-execute the ln command.
For more info, see the discussion in #363.
Regular left click on dunst is assigned to the action “close the notification” by default. To invoke the default action for the notification, please try middle click or executing a command line dunstctl action via a custom keyboard shortcut instead.
If you like the behavior similar to the one on other platforms like Windows (regular left click to invoke the default action), setting the option mouse_left_click in the dunstrc to do_action, close_current will help you.
Your new shell has to be able to execute commands as dunst’s user and you have to export the DBUS_SESSION_BUS_ADDRESS environment variable with the same content it would have in your desktop session.
Usually, the environment variable’s content is DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/<UID>/bus. On older systems, this may not be the case and may change on a per-session basis.
alias notify-send="sudo -u USERNAME DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/<UID>/bus notify-send"
Any other combination, executing notify-send with the valid DBUS_SESSION_BUS_ADDRESS-variable and user should work.