Comment # 40 on bug 1183727 from Jonathan Kang

When Wi-Fi was turned off when shutting down the system, NetworkManager tried
to
call the dispatcher script for the "pre-down" action. This script, if called,
will find mounted nfs mounts in /etc/fstab and tries to unmount them.

> May 25 17:58:41 jlinn dbus-daemon[1328]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.7' (uid=0 pid=1734 comm="/usr/sbin/NetworkManager --no-daemon ")

As this is in the shutdown phase, dbus-daemon refuses this activation. However,
it's the DBus user message bus rather than the system message bus that is
shutting down. Is this an DBus issue that blocks the activation?

> May 25 17:58:41 jlinn dbus-daemon[1328]: [system] Activation via systemd failed for unit 'dbus-org.freedesktop.nm-dispatcher.service': Refusing activation, D-Bus is shutting down.