diff --git a/dvc/project.py b/dvc/project.py
index 0ce183565..be08b2ae8 100644
--- a/dvc/project.py
+++ b/dvc/project.py
@@ -248,6 +248,10 @@ class Project(object):
                                     outs=[f],
                                     add=True)
 
+                if stage is None:
+                    stages.append(stage)
+                    continue
+
                 self._check_output_duplication(stage.outs, all_stages)
 
                 stage.save()
@@ -414,6 +418,9 @@ class Project(object):
                             deps=[url],
                             outs=[out])
 
+        if stage is None:
+            return None
+
         self._check_output_duplication(stage.outs, self.stages())
         self._check_circular_dependency(stage.deps, stage.outs)
 
diff --git a/tests/test_add.py b/tests/test_add.py
index 8b9e1af2b..d41d845e0 100644
--- a/tests/test_add.py
+++ b/tests/test_add.py
@@ -1,5 +1,6 @@
 import os
 import stat
+import time
 import shutil
 import filecmp
 
@@ -113,6 +114,9 @@ class TestAddModifiedDir(TestDvc):
         self.assertEqual(len(stages), 1)
         self.assertTrue(stages[0] is not None)
         os.unlink(self.DATA)
+
+        time.sleep(2)
+
         stages = self.dvc.add(self.DATA_DIR)
         self.assertEqual(len(stages), 1)
         self.assertTrue(stages[0] is not None)