When the Install Updates button is pressed in the Update Manager, the Update Manager freezes.

Update and upgrade did not solve the issue.

I am getting the following error message:

Traceback (most recent call last):

  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 475, in _inline_callbacks

    result = gen.send(result)

  File "/usr/lib/python2.7/dist-packages/aptdaemon/client.py", line 1622, in _run_transaction_helper

    daemon = get_aptdaemon(self.bus)

  File "/usr/lib/python2.7/dist-packages/aptdaemon/client.py", line 1696, in get_aptdaemon

    False),

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 241, in get_object

    follow_name_owner_changes=follow_name_owner_changes)

  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 248, in __init__

    self._named_service = conn.activate_name_owner(bus_name)

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 180, in activate_name_owner

    self.start_service_by_name(bus_name)

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 278, in start_service_by_name

    'su', (bus_name, flags)))

  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking

    message, timeout)

dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1

Traceback (most recent call last):

  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 475, in _inline_callbacks

    result = gen.send(result)

  File "/usr/lib/python2.7/dist-packages/aptdaemon/client.py", line 1622, in _run_transaction_helper

    daemon = get_aptdaemon(self.bus)

  File "/usr/lib/python2.7/dist-packages/aptdaemon/client.py", line 1696, in get_aptdaemon

    False),

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 241, in get_object

    follow_name_owner_changes=follow_name_owner_changes)

  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 248, in __init__

    self._named_service = conn.activate_name_owner(bus_name)

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 180, in activate_name_owner

    self.start_service_by_name(bus_name)

  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 278, in start_service_by_name

    'su', (bus_name, flags)))

  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 651, in call_blocking

    message, timeout)

dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1

dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1

Traceback (most recent call last):

  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 473, in _inline_callbacks

    result = gen.throw(result.type, result.value, result.traceback)

  File "/usr/lib/python2.7/dist-packages/UpdateManager/backend/InstallBackendAptdaemon.py", line 52, in commit

    downgrade, defer=True)

dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1