diff --git a/data/mesh_ingestor/providers/meshcore.py b/data/mesh_ingestor/providers/meshcore.py
index 25175ac..c06bb7a 100644
--- a/data/mesh_ingestor/providers/meshcore.py
+++ b/data/mesh_ingestor/providers/meshcore.py
@@ -639,6 +639,13 @@ async def _run_meshcore(
     """
     from meshcore import EventType, MeshCore
 
+    # Install early so :meth:`_MeshcoreInterface.close` can signal shutdown with
+    # ``stop_event.set()`` instead of ``loop.stop()`` while ``connect()`` or the
+    # ``finally`` disconnect is still running (avoids RuntimeError from
+    # :meth:`asyncio.loop.run_until_complete`).
+    stop_event = asyncio.Event()
+    iface._stop_event = stop_event
+
     mc: MeshCore | None = None
     try:
         cx = _make_connection(target, _DEFAULT_BAUDRATE)
@@ -682,6 +689,11 @@ async def _run_meshcore(
                 "firmware."
             )
 
+        if stop_event.is_set():
+            raise ConnectionError(
+                "Mesh interface close was requested before the connection could be completed."
+            )
+
         iface.isConnected = True
         connected_event.set()
 
@@ -698,8 +710,6 @@ async def _run_meshcore(
 
         await mc.start_auto_message_fetching()
 
-        stop_event = asyncio.Event()
-        iface._stop_event = stop_event
         await stop_event.wait()
 
     except Exception as exc:
diff --git a/tests/test_provider_unit.py b/tests/test_provider_unit.py
index 35fe12f..8979ee3 100644
--- a/tests/test_provider_unit.py
+++ b/tests/test_provider_unit.py
@@ -17,6 +17,7 @@ from __future__ import annotations
 
 import sys
 import types
+from contextlib import suppress
 from pathlib import Path
 
 import pytest
@@ -1307,6 +1308,7 @@ def _make_fake_meshcore_mod(
     connect_result: object = "ok",
     fail_ensure_contacts: bool = False,
     disconnect_raises: bool = False,
+    connect_stall_event=None,
 ):
     """Build a minimal fake ``meshcore`` module for testing :func:`_run_meshcore`.
 
@@ -1317,6 +1319,8 @@ def _make_fake_meshcore_mod(
             ``RuntimeError``.
         disconnect_raises: When ``True``, ``mc.disconnect()`` raises, exercising
             the ``finally`` exception-suppression path.
+        connect_stall_event: Optional :class:`asyncio.Event`; when set,
+            ``connect()`` awaits it (never completes unless the event is set).
     """
     import enum
 
@@ -1351,6 +1355,8 @@ def _make_fake_meshcore_mod(
                 self._catch_all = callback
 
         async def connect(self):
+            if connect_stall_event is not None:
+                await connect_stall_event.wait()
             return connect_result
 
         async def ensure_contacts(self):
@@ -1405,6 +1411,40 @@ async def _run_until_connected(iface, target, fake_mod, mod):
     return connected_event, error_holder
 
 
+def test_run_meshcore_stop_event_before_connect_finishes(monkeypatch):
+    """_stop_event must exist before connect() returns so iface.close() avoids loop.stop()."""
+    import asyncio
+    import threading
+
+    import data.mesh_ingestor.providers.meshcore as _mod
+
+    monkeypatch.setattr(_mod.config, "_debug_log", lambda *_a, **_k: None)
+    stall = asyncio.Event()
+    fake_mod = _make_fake_meshcore_mod(connect_stall_event=stall)
+    monkeypatch.setitem(sys.modules, "meshcore", fake_mod)
+
+    async def _runner() -> None:
+        iface = _MeshcoreInterface(target=None)
+        connected_event = threading.Event()
+        error_holder: list = [None]
+        task = asyncio.create_task(
+            _mod._run_meshcore(iface, "/dev/ttyUSB0", connected_event, error_holder)
+        )
+        for _ in range(500):
+            await asyncio.sleep(0)
+            if iface._stop_event is not None:
+                break
+        assert (
+            iface._stop_event is not None
+        ), "_stop_event must be set before connect() completes"
+        assert not connected_event.is_set()
+        task.cancel()
+        with suppress(asyncio.CancelledError):
+            await task
+
+    asyncio.run(_runner())
+
+
 def test_run_meshcore_happy_path(monkeypatch):
     """_run_meshcore must signal connected and leave isConnected=True on success."""
     import asyncio