I have exactly the same problem after upgrading from 14.04 to 15.10. I have two users (referred here as X and Y) in sudo group. When I run 'pkexec bash' from terminal I get following message. It doesn't make any difference if I try to authenticate as X or Y.
==== AUTHENTICATING FOR org.freedesktop.policykit.exec === Authentication is needed to run `/bin/bash' as the super user Multiple identities can be used for authentication: 1. X,,, (X) 2. ,,, (Y) Choose identity to authenticate as (1-2): 1 Password: polkit-agent-helper-1: error response to PolicyKit daemon: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for cookie ==== AUTHENTICATION FAILED === Error executing command as another user: Not authorized This incident has been reported. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1288786 Title: pkexec does not launch graphical authentication To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/policykit-1/+bug/1288786/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
