package nvidia-prime (not installed) failed to install/upgrade: subprocess installed post-removal script returned error exit status 2

[Tim B]

Description: Ubuntu 16.04.6 LTS
Release: 16.04

Hi,
I have decided to upgrade from 14.04 to 16.04.
Previously no problems with NVIDIA graphics card
Since upgrade the login often looped (logged me out again automatically)
and would not allow a change to the TTYs (Alt-Ctrl-F1 etc)
Attempt to install nvidia-prime and nvidia-430 both seem to go awry.
It starts now but is using the "Intel Ivybridge Mobile" drivers.
Lots of problems coming up around "com.ubuntu.apport.apport-gtk-root"

Will attempt a complete re-install and see what happens.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: nvidia-prime (not installed)
ProcVersionSignature: Ubuntu 4.4.0-173.203-generic 4.4.208
Uname: Linux 4.4.0-173-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.21
Architecture: amd64
Date: Fri Feb 14 11:59:04 2020
Df:

ErrorMessage: subprocess installed post-removal script returned error exit status 2
InstallationDate: Installed on 2014-12-25 (1876 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.6
 apt 1.2.32
SourcePackage: nvidia-prime
Title: package nvidia-prime (not installed) failed to install/upgrade: subprocess installed post-removal script returned error exit status 2
UpgradeStatus: Upgraded to xenial on 2020-02-13 (0 days ago)