Without a reboot, I still get the same error with the new policykit package from vivid-proposed. When I do this: # apt-get purge apport policykit-1 # apt-get autoremove Then do a system reboot, followed by: # apt-get install apport Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: apport-symptoms libpolkit-agent-1-0 libpolkit-backend-1-0 policykit-1 python3-apport python3-problem-report Suggested packages: apport-gtk apport-kde python3-launchpadlib The following NEW packages will be installed: apport apport-symptoms libpolkit-agent-1-0 libpolkit-backend-1-0 policykit-1 python3-apport python3-problem-report 0 upgraded, 7 newly installed, 0 to remove and 9 not upgraded. Need to get 202 kB/316 kB of archives. After this operation, 2,221 kB of additional disk space will be used. Do you want to continue? [Y/n] y Get:1 http://us.archive.ubuntu.com/ubuntu/ vivid-proposed/main libpolkit-agent-1-0 amd64 0.105-8ubuntu3 [15.2 kB] Get:2 http://us.archive.ubuntu.com/ubuntu/ vivid-proposed/main libpolkit-backend-1-0 amd64 0.105-8ubuntu3 [35.7 kB] Get:3 http://us.archive.ubuntu.com/ubuntu/ vivid/main python3-problem-report all 2.17.2-0ubuntu1 [9,950 B] Get:4 http://us.archive.ubuntu.com/ubuntu/ vivid/main python3-apport all 2.17.2-0ubuntu1 [75.7 kB] Get:5 http://us.archive.ubuntu.com/ubuntu/ vivid/main apport-symptoms all 0.20 [14.2 kB] Get:6 http://us.archive.ubuntu.com/ubuntu/ vivid-proposed/main policykit-1 amd64 0.105-8ubuntu3 [51.6 kB] Fetched 202 kB in 1s (124 kB/s) Selecting previously unselected package libpolkit-agent-1-0:amd64. (Reading database ... 68327 files and directories currently installed.) Preparing to unpack .../libpolkit-agent-1-0_0.105-8ubuntu3_amd64.deb ... Unpacking libpolkit-agent-1-0:amd64 (0.105-8ubuntu3) ... Selecting previously unselected package libpolkit-backend-1-0:amd64. Preparing to unpack .../libpolkit-backend-1-0_0.105-8ubuntu3_amd64.deb ... Unpacking libpolkit-backend-1-0:amd64 (0.105-8ubuntu3) ... Selecting previously unselected package python3-problem-report. Preparing to unpack .../python3-problem-report_2.17.2-0ubuntu1_all.deb ... Unpacking python3-problem-report (2.17.2-0ubuntu1) ... Selecting previously unselected package python3-apport. Preparing to unpack .../python3-apport_2.17.2-0ubuntu1_all.deb ... Unpacking python3-apport (2.17.2-0ubuntu1) ... Selecting previously unselected package apport. Preparing to unpack .../apport_2.17.2-0ubuntu1_all.deb ... Unpacking apport (2.17.2-0ubuntu1) ... Selecting previously unselected package apport-symptoms. Preparing to unpack .../apport-symptoms_0.20_all.deb ... Unpacking apport-symptoms (0.20) ... Selecting previously unselected package policykit-1. Preparing to unpack .../policykit-1_0.105-8ubuntu3_amd64.deb ... Unpacking policykit-1 (0.105-8ubuntu3) ... Processing triggers for shared-mime-info (1.3-1) ... Processing triggers for hicolor-icon-theme (0.14-0ubuntu1) ... Processing triggers for man-db (2.7.0.2-5) ... Processing triggers for ureadahead (0.100.0-19) ... ureadahead will be reprofiled on next reboot Processing triggers for systemd (219-7ubuntu3) ... Processing triggers for dbus (1.8.12-1ubuntu5) ... Setting up libpolkit-agent-1-0:amd64 (0.105-8ubuntu3) ... Setting up libpolkit-backend-1-0:amd64 (0.105-8ubuntu3) ... Setting up python3-problem-report (2.17.2-0ubuntu1) ... Setting up python3-apport (2.17.2-0ubuntu1) ... Setting up apport (2.17.2-0ubuntu1) ... Setting up apport-symptoms (0.20) ... Setting up policykit-1 (0.105-8ubuntu3) ... PolicyKit daemon disconnected from the bus. We are no longer a registered authentication agent. Processing triggers for libc-bin (2.21-0ubuntu4) ... Processing triggers for ureadahead (0.100.0-19) ... Processing triggers for systemd (219-7ubuntu3) ... So the new package fixes the problem for people who haven't yet had a failed install, but it doesn't work to upgrade from failed install without a system reboot.