Could you please provide ~/.cache/upstart/application-legacy-puritine_firefox_0.0-.log?
Seems maybe it's not able to write to home directory that is mounted inside the container for some reason.
Could you please provide ~/.cache/ upstart/ application- legacy- puritine_ firefox_ 0.0-.log?
Seems maybe it's not able to write to home directory that is mounted inside the container for some reason.