diff --git a/pynxtools/dataconverter/helpers.py b/pynxtools/dataconverter/helpers.py
index f4ac62a32..f8cedb6fc 100644
--- a/pynxtools/dataconverter/helpers.py
+++ b/pynxtools/dataconverter/helpers.py
@@ -858,7 +858,7 @@ def set_default_group(template):
     # defalut attribute key to the list of immediate child group
     dflt_key_to_grp_li: Optional[dict[str, list]] = {}
     # defalut attribute key to the group set by reader
-    dflt_key_to_exist_grp: dict[str, str] = {}
+    dflt_key_to_exist_grp: Optional[dict[str, str]] = {}
 
     # "/abc[DATA]/XYe[anything]/mnf[MNYZ]/anything" -> ['DATA', 'anything', 'MNYZ']
     pattern = r"\[(.*?)\]"
@@ -870,7 +870,7 @@ def set_default_group(template):
         # Cancel out the attribuutes
         if groups_list[-1].startswith("@"):
             continue
-        # Cancel out the fields
+        # Cancel out the fields and end groups without fields
         groups_list = groups_list[0:-1]
         if not groups_list:
             continue
@@ -893,6 +893,7 @@ def set_default_group(template):
                 dflt_key_to_grp_li[last_default_atttr] = {}
                 # Data groups
                 dflt_key_to_grp_li[last_default_atttr]["data"] = []
+                # Entry groups
                 dflt_key_to_grp_li[last_default_atttr]["entry"] = []
                 # Other groups
                 dflt_key_to_grp_li[last_default_atttr]["other"] = []
@@ -915,8 +916,8 @@ def set_default_group(template):
 
     for deflt_key, value in dflt_key_to_grp_li.items():
         pre_defalt_grp = dflt_key_to_exist_grp.get(deflt_key, None)
-        # Verify if user added the group here
-        if not pre_defalt_grp:
+        # Verify if user has added the group in default attribute
+        if pre_defalt_grp:
             if (
                 pre_defalt_grp in value["entry"]
                 or pre_defalt_grp in value["data"]
@@ -929,6 +930,11 @@ def set_default_group(template):
         if entry_default == deflt_key:
             template[entry_default] = entry_data_rnd
             continue
+        # Handle root level default
+        root_deflt = "/@default"
+        if deflt_key == root_deflt:
+            template[root_deflt] = entry_data_rnd
+            continue
 
         if value["entry"]:
             template[deflt_key] = value["entry"][0]
diff --git a/tests/dataconverter/test_helpers.py b/tests/dataconverter/test_helpers.py
index 70e1b0226..88e86d781 100644
--- a/tests/dataconverter/test_helpers.py
+++ b/tests/dataconverter/test_helpers.py
@@ -463,30 +463,48 @@ def test_path_in_data_dict(nxdl_path, expected, template):
     assert helpers.path_in_data_dict(nxdl_path, tuple(template.keys())) == expected
 
 
-def test_set_default_group(template):
+@pytest.mark.parametrize(
+    "temp_dict",
+    [
+        {
+            "/ENTRY[entry1]/NXODD_name[nxodd_name]/float_value": 2.0,
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/float_value": 8.0,
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/DATA[data1]/data1": [3, 5, 6],
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/DATA[data2]/data2": [3, 5, 6],
+        }
+    ],
+)
+def test_set_default_group(temp_dict):
     """_summary_
 
     Parameters
     ----------
     template : Template
     """
+    template = Template(temp_dict)
     assert (
         "/@default" not in template
     ), "To test the root level /@default should be empty."
     assert (
-        "/ENTRY[entry]/@default" not in template
+        "/ENTRY[entry1]/@default" not in template
     ), "To test default attribute, entry attribute should be empty."
 
     set_default_group(template)
 
-    assert (
-        template["/@default"] == "entry",
-        "To test the root level /@default should be empty.",
-    )
-    assert (
-        template["/ENTRY[entry]/@default"] == "nxodd_name",
-        "To test default attribute, entry attribute should be empty.",
-    )
+    assert template["/@default"] in [
+        "data1",
+        "data2",
+    ], "To test the root level /@default should be empty."
+
+    assert template["/ENTRY[entry1]/@default"] in [
+        "nxodd_name",
+        "nxodd_name_2",
+    ], "To test default attribute, entry attribute should be empty."
+
+    assert template["/ENTRY[entry1]/NXODD_name[nxodd_name_2]/@default"] in [
+        "data1",
+        "data2",
+    ], "To test default attribute, entry attribute should be empty."
 
 
 def test_atom_type_extractor_and_hill_conversion():