gconf2.0 crashes repeatedly on upgrade to focal fossa

Running update-manager -p today just before the release of focal fossa, the install halted during package configuration with a gconf2.0 crash. I had to dismiss about 30 dialogs before the install completed, each exactly the same.

I run stock ubuntu, except that I use the standard Gnome desktop instead of the Ubuntu unity Gnome variant. The machine in question has been upgraded from 18.04 to 19.10 & now to 20.04

Since this package is now marked as only required for legacy applications, perhaps it needs removing before the focal upgrade?

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.18
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CurrentDesktop: GNOME
Date: Thu Apr 23 15:43:05 2020
InstallationDate: Installed on 2018-07-19 (643 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: dist-upgrade
UpgradeStatus: Upgraded to focal on 2020-04-23 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.apport.crashdb.conf: 2019-04-29T12:11:49.292007