I am trying to upgrade from Ubuntu 16.04 LTS to 18.04 LTS.

No matter which upgrade command I try: do-release-upgrade or apt dist-upgrade, at some point in the upgrade I start getting numerous "Failed to connect to bus: No such file or directory" errors and eventually the upgrade process stops with an error and the following packages in error:

  • udev
  • gnome-bluetooth
  • x11-common
  • bluez
  • indicator-bluetooth
  • rpcbind
  • unity-control-center
  • xserver-common
  • initramfs-tools-core
  • cups-daemon
  • initramfs-tools
  • libxvmc1:amd64
  • xserver-xorg-core
  • cups-core-drivers
  • xserver-xorg-video-radeon
  • libxtst6:amd64
  • libxtst-dev:amd64
  • network-manager
  • ubuntu-drivers-common
  • xserver-xorg-video-vesa
  • software-properties-gtk
  • xserver-xorg-video-amdgpu
  • postgresql-common
  • xserver-xorg-video-tdfx
  • libice6:amd64
  • libice6:i386
  • libxt6:amd64
  • libxt6:i386
  • gnome-session-bin
  • xwayland
  • xserver-xorg-input-wacom
  • xserver-xorg-input-synaptics
  • ghostscript-x
  • xserver-xorg-video-mach64
  • libaudio2:amd64
  • xserver-xorg-video-ati
  • pulseaudio
  • xserver-xorg-video-intel
  • libxt-dev:amd64
  • xserver-xorg-video-r128
  • libqtgui4:amd64
  • gnome-settings-daemon
  • mutter
  • xserver-xorg-video-qxl
  • metacity
  • unity-settings-daemon
  • libmutter-2-0:amd64
  • x11-xkb-utils
  • vino
  • xserver-xorg-input-evdev
  • gnome-session

By manually intervening (running dpkg --configure on selected packages until all issues were resolved) I could eventually get all (remaining) packages installed and configured.

On my 3rd attempt I was able to get the furthest (by using apt dist-upgrade) but even then I could not properly reboot - the next reboot would start reasonably OK, but starting with "Login Service", several services would fail to start (in approximately this order):

  1. Login Service (systemd-logind.service)
  2. Disk Manager
  3. Modem Manager (ModemManager.service)
  4. Network Manager (NetworkManager.service)
  5. /etc/rc.local Compatibility
  6. GNOME Display Manager (gdm.service)
  7. Bluetooth Service (bluetooth.service)

Even then, X11 was unable to initialise and I had no login prompt (CTRL-ALT-F1 would not give me a login prompt).

I tried reinstalling dbus but that did not work. I'm wondering if the pam_systemd was not installed (since I was also getting D-Bus connection errors)?

Clearly I missed some required packages in the manual intervention phase. Any suggestions?

2 Answers 2


Try update/upgrade:

sudo apt update
sudo apt upgrade

Purge and install again dbus-user-session package:

sudo apt purge dbus-user-session
sudo apt install dbus-user-session
  • Indeed, I have always used update/upgrade before starting. No luck. I did a purge on dbus (which removed quite a lot) and reinstalled as much as I could remember. I will try purge and reinstall the dbus-user-session.
    – KevinM
    Commented Aug 18, 2018 at 14:43
  • @KevinM OK, write a comment what's happened after dbus-user-session package installing.
    – Bob
    Commented Aug 18, 2018 at 14:46
  • It reinstalls dbus-user-session, but the bus is still not available. A 'ps aux' shows that dbus-daemon, dbus-launch and upstart-dbus-bridge processes are running. Current errors include 'invoke-rc.d: initscript udev, action "restart" failed.' when trying to configure udev.
    – KevinM
    Commented Aug 18, 2018 at 16:50

I eventually gave up on this task. I have no idea what was wrong with my base 16.04 LTS installation, but an upgrade was impossible.

I finally had to install a new 18.04 LTS installation over my old one.


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