diff --git a/arkindex/training/serializers.py b/arkindex/training/serializers.py
index 5faa79fc6152fcb6ea3ab0a80252a8e8c7fe18e7..901b94b6d2828d7f5c585da47aa382c8ad9f9dfe 100644
--- a/arkindex/training/serializers.py
+++ b/arkindex/training/serializers.py
@@ -803,7 +803,7 @@ class SelectionDatasetElementSerializer(serializers.Serializer):
             )
         ):
             raise ValidationError([
-                f"The dataset prevent duplication and this element is already present in set {existing_set}."
+                f"The dataset prevent duplication and some elements are already present in set {existing_set}."
             ])
         return set
 
diff --git a/arkindex/training/tests/test_datasets_api.py b/arkindex/training/tests/test_datasets_api.py
index b994211562c0709f8f4b3718d51bc43923034b75..58ab00fd8327a16f87f3fe9bacebd7887fb2c3d7 100644
--- a/arkindex/training/tests/test_datasets_api.py
+++ b/arkindex/training/tests/test_datasets_api.py
@@ -1761,7 +1761,7 @@ class TestDatasetsAPI(FixtureAPITestCase):
             )
             self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
         self.assertDictEqual(response.json(), {
-            "set_id": ["The dataset prevent duplication and this element is already present in set training."]
+            "set_id": ["The dataset prevent duplication and some elements are already present in set training."]
         })
 
     def test_add_from_selection_allow_dupes(self):