I installed dbus-user-session but it doesn't look functional:

$ ls -lh $XDG_RUNTIME_DIR/bus
ls: cannot access '/run/user/1000/bus': No such file or directory

$ systemctl --user status dbus.service
Failed to get properties: Process org.freedesktop.systemd1 exited with status 1

$ systemctl --user status dbus.socket
Failed to get properties: Process org.freedesktop.systemd1 exited with status 1

I'm not too sure if I should be manually starting it from my desktop
environment (i3 + gnome-settings-daemon), but Simon McVittie suggested I
file a bug about this (see Bug #994961).

Francois

Control: tags -1 + moreinfo
...

What's meant to happen is:

* your display manager runs the /etc/pam.d/common-session stack, which
  includes "session optional pam_systemd.so" from the libpam-systemd package

* pam_systemd tells systemd (pid 1) to start user@1000.service, which is
  systemd --user, launching default.target by default

* default.target includes dbus.socket because
  /usr/lib/systemd/user/sockets.target.wants/dbus.socket says so

* dbus.socket listens on $XDG_RUNTIME_DIR/bus

* the first time something connects to that socket, it starts dbus.service,
  which is dbus-daemon --session --address=systemd: (plus some other options)

Presumably something has gone wrong somewhere in that chain of events?

If you can't tell what's wrong by comparing the chain of events I described
with what is actually happening on your system, here are some other things
that would be useful information:

Is there a "systemd --user" process running as your uid?

Is there a "dbus-daemon --session" process running as your uid?

Is anything D-Bus-related logged in the systemd Journal when you log in?

What does `systemd-cgls` say about these various services?

    smcv