Cannot do Partial System Upgrade: Update Manager does not finish

[Detlef Lechner]

Binary package hint: update-manager

Since the last distribution upgrade two days ago I cannot do Partial System Upgrade: Update Manager does not finish The Partial System Upgrade says that it is calculating. A dialog window appears without any content. I cannot get rid of this dialog window. From then onwards, the process update-manager takes 96% of the CPU time.
I tried this several times yesterday and today.
Once I saw a message that the "Legitimation service of Policy Kit has been terminated unexpectedly."

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.146.5
ProcVersionSignature: Ubuntu 2.6.38-7.37-generic 2.6.38
Uname: Linux 2.6.38-7-generic i686
Architecture: i386
Date: Thu Mar 24 07:52:18 2011
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
ProcEnviron:
 LANGUAGE=de_DE:en
 PATH=(custom, user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to natty on 2011-03-24 (0 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[dino99 (9d9)]

That version is no more maintained