diff --git a/nilmdb/utils/mustclose.py b/nilmdb/utils/mustclose.py
index 468ace2..00577ef 100644
--- a/nilmdb/utils/mustclose.py
+++ b/nilmdb/utils/mustclose.py
@@ -28,10 +28,13 @@ def must_close(errorfile = sys.stderr, wrap_verify = False):
 
         @wrap_class_method
         def __del__(orig, self, *args, **kwargs):
-            if "_must_close" in self.__dict__:
-                fprintf(errorfile, "error: %s.close() wasn't called!\n",
-                        self.__class__.__name__)
-            return orig(self, *args, **kwargs)
+            try:
+                if "_must_close" in self.__dict__:
+                    fprintf(errorfile, "error: %s.close() wasn't called!\n",
+                            self.__class__.__name__)
+                return orig(self, *args, **kwargs)
+            except: # pragma: no cover
+                pass
 
         @wrap_class_method
         def close(orig, self, *args, **kwargs):
diff --git a/nilmdb/utils/serializer.py b/nilmdb/utils/serializer.py
index 4ffa3c4..1dff4a0 100644
--- a/nilmdb/utils/serializer.py
+++ b/nilmdb/utils/serializer.py
@@ -120,7 +120,7 @@ def serializer_proxy(obj_or_type):
             try:
                 self.__call_queue.put((None, None, None, None))
                 self.__thread.join()
-            except TypeError: # pragma: no cover
+            except: # pragma: no cover
                 pass
 
     return SerializerObjectProxy(obj_or_type)