diff --git a/nova/conductor/manager.py b/nova/conductor/manager.py
index 4956b3d46700..d7a2eb9a042f 100644
--- a/nova/conductor/manager.py
+++ b/nova/conductor/manager.py
@@ -411,8 +411,10 @@ class ComputeTaskManager(base.Base):
                           ' %(dest)s unexpectedly failed.'),
                       {'instance_id': instance.uuid, 'dest': destination},
                       exc_info=True)
+            # Reset the task state to None to indicate completion of
+            # the operation as it is done in case of known exceptions.
             _set_vm_state(context, instance, ex, vm_states.ERROR,
-                          instance.task_state)
+                          task_state=None)
             migration.status = 'error'
             migration.save()
             raise exception.MigrationError(reason=six.text_type(ex))
diff --git a/nova/tests/unit/conductor/test_conductor.py b/nova/tests/unit/conductor/test_conductor.py
index ff046f527eb5..a436d283c1bb 100644
--- a/nova/tests/unit/conductor/test_conductor.py
+++ b/nova/tests/unit/conductor/test_conductor.py
@@ -1858,7 +1858,7 @@ class ConductorTaskTestCase(_BaseTaskTestCase, test_compute.BaseTestCase):
                         instance['uuid'],
                         'compute_task', 'migrate_server',
                         dict(vm_state=vm_states.ERROR,
-                             task_state=inst_obj.task_state,
+                             task_state=None,
                              expected_task_state=task_states.MIGRATING,),
                         expected_ex, request_spec)
         self.assertEqual(ex.kwargs['reason'], six.text_type(expected_ex))