I have found the solution by happenstance: (I am using XFCE in German, so maybe the wording I describe here is not 100% accurate) In the XFCE settings menu -> Session management -> Automatically started applications, there is an Item "Policykit Authentication Agent". This was unchecked. Re-check, reboot (probably logout and login is sufficient), and it is back working.
But: I am absolutely sure I did not remove the check. On one of the affected computers, I have never been in this dialog before. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/976638 Title: pkexec does not find any authentication agent To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/policykit-1/+bug/976638/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
