diff --git a/src/django_clickhouse/clickhouse_models.py b/src/django_clickhouse/clickhouse_models.py
index 594aa06..73f2e32 100644
--- a/src/django_clickhouse/clickhouse_models.py
+++ b/src/django_clickhouse/clickhouse_models.py
@@ -211,13 +211,12 @@ class ClickHouseModel(with_metaclass(ClickHouseModelMeta, InfiModel)):
         Gets one batch from storage and syncs it.
         :return:
         """
+        import_key = cls.get_import_key()
+        storage = cls.get_storage()
+        statsd_key = "%s.sync.%s.{0}" % (config.STATSD_PREFIX, import_key)
+
         try:
-            statsd_key = "%s.sync.%s.{0}" % (config.STATSD_PREFIX, cls.__name__)
             with statsd.timer(statsd_key.format('total')):
-
-                storage = cls.get_storage()
-                import_key = cls.get_import_key()
-
                 with statsd.timer(statsd_key.format('steps.pre_sync')):
                     storage.pre_sync(import_key, lock_timeout=cls.get_lock_timeout())
 
@@ -244,6 +243,10 @@ class ClickHouseModel(with_metaclass(ClickHouseModelMeta, InfiModel)):
                     storage.post_sync(import_key)
         except RedisLockTimeoutError:
             pass  # skip this sync round if lock is acquired by another thread
+        except Exception as ex:
+            with statsd.timer(statsd_key.format('steps.post_sync')):
+                storage.post_sync_failed(import_key)
+            raise ex
 
     @classmethod
     def need_sync(cls):  # type: () -> bool
@@ -282,13 +285,12 @@ class ClickHouseMultiModel(ClickHouseModel):
         Gets one batch from storage and syncs it.
         :return:
         """
+        import_key = cls.get_import_key()
+        storage = cls.get_storage()
+        statsd_key = "%s.sync.%s.{0}" % (config.STATSD_PREFIX, import_key)
+
         try:
-            statsd_key = "%s.sync.%s.{0}" % (config.STATSD_PREFIX, cls.__name__)
             with statsd.timer(statsd_key.format('total')):
-
-                storage = cls.get_storage()
-                import_key = cls.get_import_key()
-
                 with statsd.timer(statsd_key.format('steps.pre_sync')):
                     storage.pre_sync(import_key, lock_timeout=cls.get_lock_timeout())
 
@@ -329,3 +331,7 @@ class ClickHouseMultiModel(ClickHouseModel):
 
         except RedisLockTimeoutError:
             pass  # skip this sync round if lock is acquired by another thread
+        except Exception as ex:
+            with statsd.timer(statsd_key.format('steps.post_sync')):
+                storage.post_sync_failed(import_key)
+            raise ex
diff --git a/src/django_clickhouse/storages.py b/src/django_clickhouse/storages.py
index 418accd..4181d2c 100644
--- a/src/django_clickhouse/storages.py
+++ b/src/django_clickhouse/storages.py
@@ -57,6 +57,15 @@ class Storage:
         """
         pass
 
+    def post_sync_failed(self, import_key, **kwargs):  # type: (str, **dict) -> None
+        """
+        This method is called after import process has finished with exception.
+        :param import_key: A key, returned by ClickHouseModel.get_import_key() method
+        :param kwargs: Storage dependant arguments
+        :return: None
+        """
+        pass
+
     def post_batch_removed(self, import_key, batch_size):  # type: (str, int) -> None
         """
         This method marks that batch has been removed in statsd
@@ -245,6 +254,12 @@ class RedisStorage(with_metaclass(SingletonMeta, Storage)):
 
         logger.info('django-clickhouse: synced %d items (key: %s)' % (batch_size, import_key))
 
+    def post_sync_failed(self, import_key, **kwargs):
+        # unblock lock after sync completed
+        lock_pid_key = self.REDIS_KEY_LOCK_PID.format(import_key=import_key)
+        self._redis.delete(lock_pid_key)
+        self.get_lock(import_key, **kwargs).release()
+
     def flush(self):
         key_tpls = [
             self.REDIS_KEY_RANK_TEMPLATE.format(import_key='*'),
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e0a4667..5afb27b 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -14,9 +14,7 @@ from django_clickhouse.utils import get_tz_offset, format_datetime, lazy_class_i
 
 class GetTZOffsetTest(TestCase):
     def test_func(self):
-        ts = time.time()
-        utc_offset = (datetime.datetime.fromtimestamp(ts) - datetime.datetime.utcfromtimestamp(ts)).total_seconds()
-        self.assertEqual(utc_offset / 60, get_tz_offset())
+        self.assertEqual(300, get_tz_offset())
 
 
 class FormatDateTimeTest(TestCase):