diff --git a/gnes/base/__init__.py b/gnes/base/__init__.py
index 3578af9a..5d30d0bf 100644
--- a/gnes/base/__init__.py
+++ b/gnes/base/__init__.py
@@ -227,9 +227,9 @@ def __setstate__(self, d):
         self.logger = set_logger(self.__class__.__name__, self.verbose)
         try:
             self._post_init_wrapper()
-        except ImportError:
-            self.logger.info('ImportError is often caused by a missing component, '
-                             'which often can be solved by "pip install" relevant package.')
+        except ImportError as ex:
+            self.logger.warning('ImportError is often caused by a missing component, '
+                                'which often can be solved by "pip install" relevant package. %s' % ex, exc_info=True)
 
     def train(self, *args, **kwargs):
         """
@@ -248,7 +248,7 @@ def dump(self, filename: str = None) -> None:
             f = tempfile.NamedTemporaryFile('w', delete=False, dir=os.environ.get('GNES_VOLUME', None)).name
         with open(f, 'wb') as fp:
             pickle.dump(self, fp)
-        self.logger.info('model is stored to %s' % f)
+        self.logger.critical('model is serialized to %s' % f)
 
     @profiling
     def dump_yaml(self, filename: str = None) -> None:
@@ -334,7 +334,7 @@ def _get_instance_from_yaml(cls, constructor, node, stop_on_import_error=False):
         load_from_dump = False
         if dump_path:
             obj = cls.load(dump_path)
-            obj.logger.info('restore %s from %s' % (cls.__name__, dump_path))
+            obj.logger.critical('restore %s from %s' % (cls.__name__, dump_path))
             load_from_dump = True
         else:
             cls.init_from_yaml = True
@@ -351,7 +351,7 @@ def _get_instance_from_yaml(cls, constructor, node, stop_on_import_error=False):
                 tmp_p = {kk: _expand_env_var(vv) for kk, vv in data.get('parameters', {}).items()}
                 obj = cls(**tmp_p, gnes_config=data.get('gnes_config', {}))
 
-            obj.logger.info('initialize %s from a yaml config' % cls.__name__)
+            obj.logger.critical('initialize %s from a yaml config' % cls.__name__)
             cls.init_from_yaml = False
 
         if node.tag in {'!PipelineEncoder', '!CompositionalTrainableBase'}:
diff --git a/gnes/preprocessor/audio/audio_vanilla.py b/gnes/preprocessor/audio/audio_vanilla.py
index e587ce96..9079b360 100644
--- a/gnes/preprocessor/audio/audio_vanilla.py
+++ b/gnes/preprocessor/audio/audio_vanilla.py
@@ -40,6 +40,6 @@ def apply(self, doc: 'gnes_pb2.Document') -> None:
                     c.offset = ci
                     c.weight = 1 / len(audio)
             else:
-                self.logger.info('bad document: no audio extracted')
+                self.logger.warning('bad document: no audio extracted')
         else:
             self.logger.error('bad document: "raw_bytes" is empty!')
diff --git a/gnes/preprocessor/video/ffmpeg.py b/gnes/preprocessor/video/ffmpeg.py
index d0be4372..b067c411 100644
--- a/gnes/preprocessor/video/ffmpeg.py
+++ b/gnes/preprocessor/video/ffmpeg.py
@@ -178,7 +178,7 @@ def apply(self, doc: 'gnes_pb2.Document') -> None:
                     c.weight = 1 / len(sub_videos)
 
             else:
-                self.logger.info('bad document: no key frames extracted')
+                self.logger.warning('bad document: no key frames extracted')
         else:
             self.logger.error('bad document: "raw_bytes" is empty!')