package ifupdown 0.8.10ubuntu1.2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[David Newey]

Was applying an automatic software update when I got a failure message and this appeared!

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: ifupdown 0.8.10ubuntu1.2
ProcVersionSignature: Ubuntu 3.13.0-92.139-generic 3.13.11-ckt39
Uname: Linux 3.13.0-92-generic i686
ApportVersion: 2.20.1-0ubuntu2.4
Architecture: i386
Date: Thu Jan 5 09:00:45 2017
DpkgHistoryLog:
 Start-Date: 2017-01-05 09:00:29
 Commandline: aptdaemon role='role-commit-packages' sender=':1.96'
 Upgrade: grub-common:i386 (2.02~beta2-36ubuntu3.2, 2.02~beta2-36ubuntu3.6), grub2-common:i386 (2.02~beta2-36ubuntu3.2, 2.02~beta2-36ubuntu3.6), grub-pc:i386 (2.02~beta2-36ubuntu3.2, 2.02~beta2-36ubuntu3.6), grub-pc-bin:i386 (2.02~beta2-36ubuntu3.2, 2.02~beta2-36ubuntu3.6)
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2013-01-03 (1462 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.15ubuntu0.2
SourcePackage: ifupdown
Title: package ifupdown 0.8.10ubuntu1.2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2016-08-01 (156 days ago)