package clamav-freshclam 0.100.1+dfsg-1ubuntu0.14.04.3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 128

[William Acuna]

Update stops 3/4 of the way and shows that an error ocurred.

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: clamav-freshclam 0.100.1+dfsg-1ubuntu0.14.04.3
ProcVersionSignature: Ubuntu 4.4.0-119.143~14.04.1-generic 4.4.114
Uname: Linux 4.4.0-119-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.29
Architecture: amd64
Date: Sun Aug 19 10:20:41 2018
DuplicateSignature: package:clamav-freshclam:0.100.1+dfsg-1ubuntu0.14.04.3:subprocess installed post-installation script returned error exit status 128
ErrorMessage: subprocess installed post-installation script returned error exit status 128
InstallationDate: Installed on 2017-01-27 (569 days ago)
InstallationMedia: Ubuntu 12.04.5 LTS "Precise Pangolin" - Release amd64 (20140807.1)
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-4.4.0-119-generic root=UUID=edeed6db-9a71-4dd2-8744-914bcae3c578 ro quiet splash
RelatedPackageVersions:
 dpkg 1.17.5ubuntu5.8
 apt 1.0.1ubuntu2.18
SourcePackage: clamav
Title: package clamav-freshclam 0.100.1+dfsg-1ubuntu0.14.04.3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 128
UpgradeStatus: Upgraded to trusty on 2017-01-27 (569 days ago)

[Christian Ehrhardt  (paelzer)]

This appears to be a dup of bug 1679435

There is plenty of detail to be found, but the most important TL;DR for you is that it usually goes away by either of:
1. re-running theinstall/update
2. running the install/update in a console like
   $ sudo apt upgrade