update-manager crashed with ImportError in /usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeQuirks.py: No module named plugincore.manager

[Robin Catling]

Update manager in Quantal daily 20/6/12; fresh install in VirtualBox 4.1.16, no Guest Additions, VESA: Oracle VM VirtualBox VBE Adapter.

Running software update, recommended Partial Upgrade, then crashed. Updater coincidentally failed to lock apt as Additional Drivers kicked in on Notification area (not an unknown fault). Apport bug reporter fired up to bring directly into Launchpad.

No log files in /var/log/dist-upgrade/

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: update-manager 1:0.163
ProcVersionSignature: Ubuntu 3.4.0-5.11-generic 3.4.0
Uname: Linux 3.4.0-5-generic i686
ApportVersion: 2.2.3-0ubuntu4
Architecture: i386
CurrentDmesg.txt:
 [ 32.896109] eth0: no IPv6 routers present
 [ 43.847150] init: plymouth-stop pre-start process (1101) terminated with status 1
Date: Wed Jun 20 14:56:09 2012
DuplicateOf: https://bugs.launchpad.net/bugs/1013490
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:

InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120619)
InterpreterPath: /usr/bin/python3.2mu
PackageArchitecture: all
ProcCmdline: /usr/bin/python3.2 /usr/bin/update-manager --dist-upgrade
ProcCwd: /
ProcEnviron:
 PATH=(custom, no user)
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
 TERM=unknown
PythonArgs: ['/usr/bin/update-manager', '--dist-upgrade']
SourcePackage: update-manager
Title: update-manager crashed with ImportError in /usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeQuirks.py: No module named plugincore.manager
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1013490, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.