diff --git a/examples/debugging/multi_daemon_subactors.py b/examples/debugging/multi_daemon_subactors.py
new file mode 100644
index 0000000..b37f47a
--- /dev/null
+++ b/examples/debugging/multi_daemon_subactors.py
@@ -0,0 +1,31 @@
+import tractor
+import trio
+
+
+async def breakpoint_forever():
+    "Indefinitely re-enter debugger in child actor."
+    while True:
+        yield 'yo'
+        await tractor.breakpoint()
+
+
+async def name_error():
+    "Raise a ``NameError``"
+    getattr(doggypants)
+
+
+async def main():
+    """Test breakpoint in a streaming actor.
+    """
+    async with tractor.open_nursery() as n:
+
+        p0 = await n.start_actor('bp_forever', rpc_module_paths=[__name__])
+        p1 = await n.start_actor('name_error', rpc_module_paths=[__name__])
+
+        # retreive results
+        stream = await p0.run(__name__, 'breakpoint_forever')
+        await p1.run(__name__, 'name_error')
+
+
+if __name__ == '__main__':
+    tractor.run(main, debug_mode=True, loglevel='error')
diff --git a/tests/test_debugger.py b/tests/test_debugger.py
index 5ea4f71..fc94b6f 100644
--- a/tests/test_debugger.py
+++ b/tests/test_debugger.py
@@ -282,6 +282,34 @@ def test_multi_subactors(spawn):
     assert 'bdb.BdbQuit' in before
 
 
+def test_multi_daemon_subactors(spawn):
+    """Multiple daemon subactors, both erroring and breakpointing within a
+    stream.
+    """
+    child = spawn('multi_daemon_subactors')
+
+    child.expect(r"\(Pdb\+\+\)")
+
+    before = str(child.before.decode())
+    assert "Attaching pdb to actor: ('bp_forever'" in before
+
+    child.sendline('c')
+
+    # first name_error failure
+    child.expect(r"\(Pdb\+\+\)")
+    before = str(child.before.decode())
+    assert "NameError" in before
+
+    child.sendline('c')
+
+    child.expect(r"\(Pdb\+\+\)")
+    before = str(child.before.decode())
+    assert "tractor._exceptions.RemoteActorError: ('name_error'" in before
+
+    child.sendline('c')
+    child.expect(pexpect.EOF)
+
+
 def test_multi_subactors_root_errors(spawn):
     """Multiple subactors, both erroring and breakpointing as well as
     a nested subactor erroring.
diff --git a/tractor/__init__.py b/tractor/__init__.py
index 5ed843f..adaad38 100644
--- a/tractor/__init__.py
+++ b/tractor/__init__.py
@@ -20,8 +20,8 @@ from ._state import current_actor
 from . import _state
 from ._exceptions import RemoteActorError, ModuleNotExposed
 from ._debug import breakpoint, post_mortem
-from . import msg
 from . import _spawn
+from . import msg
 
 
 __all__ = [
@@ -60,16 +60,23 @@ async def _main(
     """
     logger = log.get_logger('tractor')
 
+    # mark top most level process as root actor
+    _state._runtime_vars['_is_root'] = True
+
     if start_method is not None:
         _spawn.try_set_start_method(start_method)
 
     if debug_mode and _spawn._spawn_method == 'trio':
         _state._runtime_vars['_debug_mode'] = True
+
         # expose internal debug module to every actor allowing
         # for use of ``await tractor.breakpoint()``
         kwargs.setdefault('rpc_module_paths', []).append('tractor._debug')
+
     elif debug_mode:
-        raise RuntimeError("Debug mode is only supported for the `trio` backend!")
+        raise RuntimeError(
+            "Debug mode is only supported for the `trio` backend!"
+        )
 
     main = partial(async_fn, *args)
 
@@ -134,9 +141,6 @@ def run(
 
     This is tractor's main entry and the start point for any async actor.
     """
-    # mark top most level process as root actor
-    _state._runtime_vars['_is_root'] = True
-
     return trio.run(
         partial(
             # our entry
diff --git a/tractor/_actor.py b/tractor/_actor.py
index 178e12a..6d223b0 100644
--- a/tractor/_actor.py
+++ b/tractor/_actor.py
@@ -301,7 +301,18 @@ class Actor:
         try:
             return getattr(self._mods[ns], funcname)
         except KeyError as err:
-            raise ModuleNotExposed(*err.args)
+            mne = ModuleNotExposed(*err.args)
+
+            if ns == '__main__':
+                msg = (
+                    "\n\nMake sure you exposed the current module using:\n\n"
+                    "ActorNursery.start_actor(<name>, rpc_module_paths="
+                    "[__name__])"
+                )
+
+                mne.msg += msg
+
+            raise mne
 
     async def _stream_handler(
         self,
@@ -591,7 +602,7 @@ class Actor:
                 # Receive runtime state from our parent
                 parent_data = await chan.recv()
                 log.debug(
-                    "Recieved state from parent:\n"
+                    "Received state from parent:\n"
                     f"{parent_data}"
                 )
                 accept_addr = (
@@ -599,6 +610,7 @@ class Actor:
                     parent_data.pop('bind_port'),
                 )
                 rvs = parent_data.pop('_runtime_vars')
+                log.debug(f"Runtime vars are: {rvs}")
                 rvs['_is_root'] = False
                 _state._runtime_vars.update(rvs)
 
diff --git a/tractor/_discovery.py b/tractor/_discovery.py
index 13da85d..360b16d 100644
--- a/tractor/_discovery.py
+++ b/tractor/_discovery.py
@@ -42,6 +42,7 @@ async def get_root(
 **kwargs,
 ) -> typing.AsyncGenerator[Union[Portal, LocalPortal], None]:
     host, port = _runtime_vars['_root_mailbox']
+    assert host is not None
     async with _connect_chan(host, port) as chan:
         async with open_portal(chan, **kwargs) as portal:
             yield portal