diff --git a/tensordict/_td.py b/tensordict/_td.py
index a2e0361fa..23d1d228f 100644
--- a/tensordict/_td.py
+++ b/tensordict/_td.py
@@ -2330,8 +2330,6 @@ def rename_key_(
         # these checks are not perfect, tuples that are not tuples of strings or empty
         # tuples could go through but (1) it will raise an error anyway and (2)
         # those checks are expensive when repeated often.
-        if old_key == new_key:
-            return self
         if not isinstance(old_key, (str, tuple)):
             raise TypeError(
                 f"Expected old_name to be a string or a tuple of strings but found {type(old_key)}"
@@ -2340,13 +2338,17 @@ def rename_key_(
             raise TypeError(
                 f"Expected new_name to be a string or a tuple of strings but found {type(new_key)}"
             )
+        old_key = unravel_key(old_key)
+        new_key = unravel_key(new_key)
+        if old_key == new_key:
+            return self
         if safe and (new_key in self.keys(include_nested=True)):
             raise KeyError(f"key {new_key} already present in TensorDict.")
 
         if isinstance(new_key, str):
             self._set_str(
                 new_key,
-                self.get(old_key),
+                self.get(old_key, default=NO_DEFAULT),
                 inplace=False,
                 validated=True,
                 non_blocking=False,
@@ -2354,7 +2356,7 @@ def rename_key_(
         else:
             self._set_tuple(
                 new_key,
-                self.get(old_key),
+                self.get(old_key, default=NO_DEFAULT),
                 inplace=False,
                 validated=True,
                 non_blocking=False,
@@ -4195,7 +4197,7 @@ def __contains__(self, key: NestedKey) -> bool:
                 if self.leaves_only:
                     # TODO: make this faster for LazyStacked without compromising regular
                     return not _is_tensor_collection(
-                        type(self.tensordict._get_str(key))
+                        type(self.tensordict._get_str(key, NO_DEFAULT))
                     )
                 return True
             return False
diff --git a/tensordict/utils.py b/tensordict/utils.py
index 2cb4b8d6d..67df379d8 100644
--- a/tensordict/utils.py
+++ b/tensordict/utils.py
@@ -1500,6 +1500,8 @@ def _get_leaf_tensordict(
             tensordict = hook(tensordict, key)
         else:
             tensordict = tensordict.get(key[0])
+            if tensordict is None:
+                raise KeyError
         key = key[1:]
     return tensordict, key[0]