/usr/bin/pkttyagent:5:on_request:g_closure_invoke:signal_emit_unlocked_R:g_signal_emit_valist:g_signal_emit_by_name

The Ubuntu Error Tracker has been receiving reports about a problem regarding policykit-1. This problem was most recently seen with package version 0.105-21ubuntu0.4, the problem page at https://errors.ubuntu.com/problem/4f940970302056098474b4823b71ee9602e24c84 contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/.