This is puzzling. The O_CREAT flag means the call to os.open() should create the lock file if it doesn't exist, so FileNotFoundError should never happen, unless the profile directory itself doesn't exist.
Can you check whether '/home/hadmut/.mozilla/firefox/va9ssbru.default/' exists on your system? If so, does it contain a '.parentlock' file (what are the file permissions if it does)? ** Changed in: firefox (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1857939 Title: hook /usr/share/apport/package-hooks/source_firefox.py crashed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1857939/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs