几周以来，network-manager它不再自动启动。我没有更改任何相关配置，我认为是更新破坏了它。
如果我手动运行systemctl start NetworkManager.service，一切都会正常。
当我使用以下方法检查服务状态时，systemctl status NetworkManager.service我得到：
● network.target - Network
Loaded: loaded (/lib/systemd/system/network.target; static; vendor preset: enabled)
Active: active since Mit 2017-11-08 16:16:08 CET; 10min ago
Docs: man:systemd.special(7)
http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget
journalctl -u NetworkManager给我No entries。
我已确定该功能NetworkManager.service已启用。
对于接下来该去哪里，您有什么想法吗？
编辑：journalctl -xe以下是当它不起作用时 输出的相关部分（我认为） ：
Nov 15 09:30:15 roman-ubuntu systemd[1]: Starting Raise network interfaces...
-- Subject: Unit networking.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- -- Unit networking.service has begun starting up.
Nov 15 09:30:15 roman-ubuntu ntpdate[1129]: name server cannot be used: Temporary failure in name resolution (-3)
Nov 15 09:30:15 roman-ubuntu systemd[1]: Started Raise network interfaces.
-- Subject: Unit networking.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit networking.service has finished starting up.
--
-- The start-up result is done.
Nov 15 09:30:15 roman-ubuntu systemd[1]: Reached target Network.
-- Subject: Unit network.target has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit network.target has finished starting up.
--
-- The start-up result is done.
Nov 15 09:30:15 roman-ubuntu systemd[1]: Reached target Network is Online.
-- Subject: Unit network-online.target has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit network-online.target has finished starting up.
--
-- The start-up result is done.
Nov 15 09:30:15 roman-ubuntu systemd[1]: Mounting /media/raspberrypi...
-- Subject: Unit media-raspberrypi.mount has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit media-raspberrypi.mount has begun starting up.
Nov 15 09:30:15 roman-ubuntu kernel: FS-Cache: Loaded
Nov 15 09:30:15 roman-ubuntu kernel: FS-Cache: Netfs 'cifs' registered for caching
Nov 15 09:30:15 roman-ubuntu kernel: Key type cifs.spnego registered
Nov 15 09:30:15 roman-ubuntu kernel: Key type cifs.idmap registered
Nov 15 09:30:15 roman-ubuntu mount[1141]: mount error(101): Network is unreachable
Nov 15 09:30:15 roman-ubuntu mount[1141]: Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
Nov 15 09:30:15 roman-ubuntu kernel: CIFS VFS: Error connecting to socket. Aborting operation.
Nov 15 09:30:15 roman-ubuntu kernel: CIFS VFS: cifs_mount failed w/return code = -101
Nov 15 09:30:15 roman-ubuntu systemd[1]: media-raspberrypi.mount: Mount process exited, code=exited status=32
Nov 15 09:30:15 roman-ubuntu systemd[1]: Failed to mount /media/raspberrypi.
-- Subject: Unit media-raspberrypi.mount has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit media-raspberrypi.mount has failed.
--
-- The result is failed.
Nov 15 09:30:15 roman-ubuntu systemd[1]: Dependency failed for Remote File Systems.
-- Subject: Unit remote-fs.target has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit remote-fs.target has failed.
--
-- The result is dependency.
Nov 15 09:30:15 roman-ubuntu systemd[1]: remote-fs.target: Job remote-fs.target/start failed with result 'dependency'.
Nov 15 09:30:15 roman-ubuntu systemd[1]: media-raspberrypi.mount: Unit entered failed state.
Nov 15 09:30:15 roman-ubuntu systemd[1]: Starting LSB: tape device initialization...
[...]
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: avahi-daemon 0.6.32-rc starting up.
Nov 15 09:30:15 roman-ubuntu gpu-manager[1230]: /etc/modprobe.d is not a file
Nov 15 09:30:15 roman-ubuntu gpu-manager[1230]: /etc/modprobe.d is not a file
Nov 15 09:30:15 roman-ubuntu ModemManager[1301]: <info> ModemManager (version 1.4.12) starting in system bus...
Nov 15 09:30:15 roman-ubuntu cron[1310]: (CRON) INFO (Running @reboot jobs)
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: Successfully called chroot().
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: Successfully dropped remaining capabilities.
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: No service file found in /etc/avahi/services.
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: Network interface enumeration completed.
Nov 15 09:30:15 roman-ubuntu avahi-daemon[1268]: Server startup complete. Host name is roman-ubuntu.local. Local service cookie is 122909000.
Nov 15 09:30:15 roman-ubuntu dbus[1187]: [system] Activating via systemd: service name='org.freedesktop.PolicyKit1' unit='polkitd.service'
Nov 15 09:30:15 roman-ubuntu speech-dispatcher[1167]: * speech-dispatcher disabled; edit /etc/default/speech-dispatcher
Nov 15 09:30:15 roman-ubuntu irqbalance[1186]: * Starting SMP IRQ Balancer: irqbalance
Nov 15 09:30:15 roman-ubuntu systemd[1]: Started LSB: Speech Dispatcher.
[...]
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nautilus:6206): GLib-GIO-CRITICAL **: g_dbus_interface_skeleton_unexport: assertion 'interface_->priv->connections != NULL' failed
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nautilus:6206): GLib-GIO-CRITICAL **: g_dbus_interface_skeleton_unexport: assertion 'interface_->priv->connections != NULL' failed
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nautilus:6206): Gtk-CRITICAL **: gtk_icon_theme_get_for_screen: assertion 'GDK_IS_SCREEN (screen)' failed
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nautilus:6206): GLib-GObject-WARNING **: invalid (NULL) pointer instance
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nautilus:6206): GLib-GObject-CRITICAL **: g_signal_connect_object: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
Nov 15 09:37:59 roman-ubuntu polkitd(authority=local)[1507]: Registered Authentication Agent for unix-session:c3 (system bus name :1.90 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8)
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: (nm-applet:6201): nm-applet-WARNING **: NetworkManager is not running
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: dropbox: python initialized
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: dropbox: running dropbox
Nov 15 09:37:59 roman-ubuntu gnome-session[5839]: dropbox: setting args
[...]