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 Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1857939 Title: hook /usr/share/apport/package-hooks/source_firefox.py crashed Status in firefox package in Ubuntu: Incomplete Bug description: Trying to report a firefox bug: % ubuntu-bug firefox *** Collecting problem information The collected information can be sent to the developers to improve the application. This might take a few minutes. ..................ERROR: hook /usr/share/apport/package-hooks/source_firefox.py crashed: Traceback (most recent call last): File "/usr/lib/python3/dist-packages/apport/report.py", line 205, in _run_hook symb['add_info'](report, ui) File "/usr/share/apport/package-hooks/source_firefox.py", line 1351, in add_info populate_item("Profiles", profiles.dump_profile_summaries()) File "/usr/share/apport/package-hooks/source_firefox.py", line 1286, in dump_profile_summaries running = " (In use)" if profile.running == True else "" File "/usr/share/apport/package-hooks/source_firefox.py", line 1078, in running fd = os.open(os.path.join(self.path, ".parentlock"), os.O_WRONLY|os.O_CREAT|os.O_TRUNC, 0o666) FileNotFoundError: [Errno 2] No such file or directory: '/home/hadmut/.mozilla/firefox/va9ssbru.default/.parentlock' . ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: firefox 71.0+build5-0ubuntu0.19.10.1 ProcVersionSignature: Ubuntu 5.3.0-24.26-generic 5.3.10 Uname: Linux 5.3.0-24-generic x86_64 ApportVersion: 2.20.11-0ubuntu8.2 Architecture: amd64 BuildID: 20191205203726 CurrentDesktop: LXQt Date: Tue Dec 31 00:06:23 2019 InstallationDate: Installed on 2019-11-30 (30 days ago) InstallationMedia: Lubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017.1) SourcePackage: firefox UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1857939/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp