Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/UpdateManager/Core/UpdateList.py", line 234, in _get_application_for_package
    desktop_file)
  File "/usr/lib/python3/dist-packages/gi/types.py", line 137, in constructor
    return info.invoke(cls, *args, **kwargs)
TypeError: constructor returned NULL

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdateProgress.py", line 78, in _on_backend_done
    self.window_main.start_available(not success)
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdateManager.py", line 186, in start_available
    self.refresh_cache()
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdateManager.py", line 313, in refresh_cache
    self.update_list.update(self.cache)
  File "/usr/lib/python3/dist-packages/UpdateManager/Core/UpdateList.py", line 416, in update
    self.update_groups = self._make_groups(cache, upgrade_pkgs)
  File "/usr/lib/python3/dist-packages/UpdateManager/Core/UpdateList.py", line 337, in _make_groups
    app = self._get_application_for_package(pkg)
  File "/usr/lib/python3/dist-packages/UpdateManager/Core/UpdateList.py", line 238, in _get_application_for_package
    (installed_file, e))
UnboundLocalError: local variable 'installed_file' referenced before assignment