"impossible to install a required package. Please report as bug."

[Michael Pryor]

Tried to update Ubunto 16.04. System complained that it could not install a required package and asked me to report as a bug. Tried running partial upgrade a couple times, but it not complete successfully. I had expected it to "just work."

Tried using the "Software Updater" GUI.

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.2 LTS"
NAME="Ubuntu"
VERSION="16.04.2 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.2 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.21
ProcVersionSignature: Ubuntu 4.8.0-56.61~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-56-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.6
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: MATE
Date: Sat Jun 24 22:18:15 2017
InstallationDate: Installed on 2017-06-20 (4 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: No upgrade log present (probably fresh install)
VarLogDistupgradeTermlog: