diff --git a/tractor/_root.py b/tractor/_root.py
index 1818283a..88347132 100644
--- a/tractor/_root.py
+++ b/tractor/_root.py
@@ -521,7 +521,7 @@ async def open_root_actor(
 
                     op_nested_actor_repr: str = _pformat.nest_from_op(
                         input_op='>) ',
-                        tree_str=actor.pformat(),
+                        text=actor.pformat(),
                         nest_prefix='|_',
                     )
                     logger.info(
diff --git a/tractor/_runtime.py b/tractor/_runtime.py
index e7475662..1c032eb5 100644
--- a/tractor/_runtime.py
+++ b/tractor/_runtime.py
@@ -1690,9 +1690,9 @@ async def async_main(
 
     op_nested_actor_repr: str = _pformat.nest_from_op(
         input_op=')> ',
-        tree_str=actor.pformat(),
+        text=actor.pformat(),
         nest_prefix='|_',
-        back_from_op=2,
+        nest_indent=2,
     )
     teardown_report += (
         'Actor runtime exited\n'