Install dbus-user-session by entering the following commands in the terminal:
sudo apt update sudo apt install dbus-user-session
simple interprocess messaging system (systemd --user integration)
D-Bus is a message bus, used for sending messages between applications. Conceptually, it fits somewhere in between raw sockets and CORBA in terms of complexity. . On systemd systems, this package opts in to the session model in which a user's session starts the first time they log in, and does not end until all their login sessions have ended. This model merges all parallel non-graphical login sessions (text mode, ssh, cron, etc.), and up to one graphical session, into a single "user-session" or "super-session" within which all background D-Bus services are shared. . Multiple graphical sessions per user are not currently supported in this mode; as a result, it is particularly suitable for gdm, which responds to requests to open a parallel graphical session by switching to the existing graphical session and unlocking it. . To retain dbus' traditional session semantics, in which login sessions are artificially isolated from each other, remove this package and install dbus-x11 instead. . See the dbus package description for more information about D-Bus in general.