package nvidia-331 (not installed) failed to purge: subprocess installed post-removal script returned error exit status 8

[Pedro Rebelo de Andrade]

While running a purging script to remove unused package configuration information from the system '''
sudo apt-get purge $(dpkg -l | awk '/^rc/ { print $2 }')
'''
there was a crash that automatically triggered the production and submittal of the attached files.

If run separately:
'''
username@hostname:~$ sudo apt-get purge nvidia-331
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  nvidia-331*
0 upgraded, 0 newly installed, 1 to remove and 110 not upgraded.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n]
(Reading database ... 387201 files and directories currently installed.)
Removing nvidia-331 (331.38-0ubuntu7) ...
Purging configuration files for nvidia-331 (331.38-0ubuntu7) ...
stop: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused
userdel: user nvidia-persistenced is currently used by process 1388
dpkg: error processing package nvidia-331 (--purge):
 subprocess installed post-removal script returned error exit status 8
Errors were encountered while processing:
 nvidia-331
E: Sub-process /usr/bin/dpkg returned an error code (1)
'''

This probably has to do with the fact that I have the system currently configured to run additional nvidia driver version 340.
Running ''' apt-cache show nvidia-331'''
returns (clipped out tailing PCI info for brevity):
'''
username@hostname:~$ apt-cache show nvidia-331
Package: nvidia-331
Priority: optional
Section: restricted/misc
Installed-Size: 18
Maintainer: Ubuntu Core Developers <email address hidden>
Architecture: amd64
Source: nvidia-graphics-drivers-340
Version: 340.101-0ubuntu0.16.04.1
Depends: nvidia-340
Filename: pool/restricted/n/nvidia-graphics-drivers-340/nvidia-331_340.101-0ubuntu0.16.04.1_amd64.deb
Size: 6636
MD5sum: 1a6be6ea31215bd4aaef776c23638b06
SHA1: ce94d059fb70a1d6eb4237cab40954f220f558bd
SHA256: 22a62d8c3a113a3fc89eafec118735f3ea2953c08bb9c8feb44884c2bd26f2c0
Description-en: Transitional package for nvidia-331
 This is a transitional package for nvidia-331, and can be
 safely removed after the installation is complete.
Description-md5: 3612f7cb365b0b5804f0fb129ccb1c2c
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 5y

Package: nvidia-331
Priority: optional
Section: restricted/misc
Installed-Size: 18
Maintainer: Ubuntu Core Developers <email address hidden>
Architecture: amd64
Source: nvidia-graphics-drivers-340
Version: 340.96-0ubuntu3
Depends: nvidia-340
Filename: pool/restricted/n/nvidia-graphics-drivers-340/nvidia-331_340.96-0ubuntu3_amd64.deb
Size: 4800
MD5sum: ab781dc3418c241975411a358df1394f
SHA1: a71f25d637bd32a71cb7a45e3aded90db608cdce
SHA256: 78ac9b96d777de51026338b1923d56ba583c74903fa0f6fa3a85daa16335de95
Description-en: Transitional package for nvidia-331
 This is a transitional package for nvidia-331, and can be
 safely removed after the installation is complete.
Description-md5: 3612f7cb365b0b5804f0fb129ccb1c2c
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 5y

Package: nvidia-331
Status: purge ok config-files
Priority: optional
Section: restricted/misc
Installed-Size: 177004
Maintainer: Ubuntu Core Developers <email address hidden>
Architecture: amd64
Source: nvidia-graphics-drivers-331
Version: 331.38-0ubuntu7
Replaces: nvidia-persistenced, xorg-driver-binary
Provides: nvidia-driver-binary, nvidia-persistenced, xorg-driver-binary, xorg-driver-video
Depends: x11-common (>= 1:7.0.0), make, sed (>> 3.0), dkms, linux-libc-dev, libc6-dev, patch, acpid, lib32gcc1, libc6-i386, passwd, adduser, libc6 (>= 2.2.5), libx11-6, libxext6, xorg-video-abi-11 | xorg-video-abi-12 | xorg-video-abi-13 | xorg-video-abi-14 | xorg-video-abi-15, xserver-xorg-core
Recommends: nvidia-settings (>= 331.20), nvidia-prime (>= 0.5) | bumblebee, libcuda1-331, nvidia-libopencl1-331, nvidia-opencl-icd-331
Suggests: nvidia-331-uvm
Conflicts: nvidia-persistenced, xorg-driver-binary
Description: NVIDIA binary driver - version 331.38
 The binary driver provide optimized hardware acceleration of OpenGL
 applications via a direct-rendering X Server. AGP, PCIe, SLI, TV-out
 and flat panel displays are also supported.
 .
 This package also includes the source for building the kernel module
 required by the Xorg driver, and provides NVIDIA's implementation of
 the Video Decode and presentation API. The latter enables acceleration
 for GeForce 8 and later series cards for h264 video.
 .
 Release Notes and supported GPUs:
 http://www.nvidia.com/object/linux-display-amd64-331.38-driver.html
Description-md5: bffe34a3b92177bc4f22fb5cd3664e76
Modaliases: nvidia_331(pci:v000010DEd000005E7sv*sd00000595bc03sc*i*, (...)
'''

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: nvidia-331 (not installed)
ProcVersionSignature: Ubuntu 4.4.0-62.83-generic 4.4.40
Uname: Linux 4.4.0-62-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 367.57 Mon Oct 3 20:37:01 PDT 2016
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4)
.proc.driver.nvidia.warnings.fbdev:
 Your system is not currently configured to drive a VGA console
 on the primary VGA device. The NVIDIA Linux graphics driver
 requires the use of a text-mode VGA console. Use of other console
 drivers including, but not limited to, vesafb, may result in
 corruption and stability problems, and is not supported.
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
Date: Sun Feb 19 18:06:58 2017
DistUpgraded: 2016-11-04 20:39:21,921 DEBUG icon theme changed, re-reading
DistroCodename: xenial
DistroVariant: ubuntu
ErrorMessage: subprocess installed post-removal script returned error exit status 8
GraphicsCard:
 NVIDIA Corporation GF104GLM [Quadro 4000M] [10de:0e3b] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company GF104GLM [Quadro 4000M] [103c:1630]
InstallationDate: Installed on 2014-05-15 (1010 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: Hewlett-Packard HP EliteBook 8760w
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-62-generic root=UUID=b5b137a7-9dcf-4846-b480-cd0d13679907 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.19
SourcePackage: nvidia-graphics-drivers-340
Title: package nvidia-331 (not installed) failed to install/upgrade: subprocess installed post-removal script returned error exit status 8
UpgradeStatus: Upgraded to xenial on 2016-11-04 (106 days ago)
dmi.bios.date: 05/27/2016
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 68SAD Ver. F.62
dmi.board.name: 1630
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 01.3D
dmi.chassis.asset.tag: CNU1332NF1
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr68SADVer.F.62:bd05/27/2016:svnHewlett-Packard:pnHPEliteBook8760w:pvrA0001C02:rvnHewlett-Packard:rn1630:rvrKBCVersion01.3D:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP EliteBook 8760w
dmi.product.version: A0001C02
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.2
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-0ubuntu0.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Sun Feb 19 17:55:11 2017
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.18.4-0ubuntu0.2