package gnome-session 3.26.1-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2

[Dan Pitic]

Description: Ubuntu 17.10
Release: 17.10

gnome-session 3.26.1-0ubuntu5

I tried to install gnome-session using apt using --reinstall option.
Expected the installation to reinstall gnome-session.
Received error:
update-alternatives: error: cannot stat file '/etc/alternatives/gdm3.css': Invalid argument

ProblemType: Package
DistroRelease: Ubuntu 17.10
Package: gnome-session 3.26.1-0ubuntu5
ProcVersionSignature: Ubuntu 4.13.0-16.19-lowlatency 4.13.4
Uname: Linux 4.13.0-16-lowlatency x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.20.7-0ubuntu3
AptOrdering:
 gnome-session:amd64: Install
 NULL: ConfigurePending
Architecture: amd64
Date: Mon Oct 23 19:03:46 2017
ErrorMessage: subprocess installed post-installation script returned error exit status 2
InstallationDate: Installed on 2016-07-16 (463 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Python3Details: /usr/bin/python3.6, Python 3.6.3, python3-minimal, 3.6.3-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.14, python-minimal, 2.7.14-2ubuntu1
RelatedPackageVersions:
 dpkg 1.18.24ubuntu1
 apt 1.5
SourcePackage: gnome-session
Title: package gnome-session 3.26.1-0ubuntu5 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2
UpgradeStatus: Upgraded to artful on 2017-10-19 (3 days ago)

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.

Ubuntu 17.10 (artful) reached end-of-life on July 19, 2018.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in.