Comment 9 for bug 187335

I'm having the same problem. Sometimes when I click unlock, nothing happens, and sometimes it gives me the error message about an unknown error occurring. I was already in the admin group, but I added myself to the polkitusers group and I'm still having the problem.

I'm not sure if it matters, but when I upgraded I had a lot of errors in dbus but it said it was OK because there was an upgrade in progress. Then the first boot had a lot of program crashes, but after that everything seemed fine. So perhaps this could be a dbus issue?