@@ -125,6 +125,17 @@ def start(self):
             self._java_server.start()
             self._started = True
         except Exception as e:
+            # The engine leaves cleanup to the caller after a failed start: what
+            # started before the failure (the HTTP idempotency cleaner, the security
+            # and session timers, any plugin already listening) keeps running as
+            # non-daemon threads until stop() is called, and stop() below returns at
+            # once while _started is False. Without this the process cannot exit.
+            try:
+                self._java_server.stop()
+            except (
+                Exception
+            ):  # nosec B110 - best effort; the start error is what the caller needs
+                pass
             raise ArcadeDBError(f"Failed to start server: {e}") from e
 
     def stop(self):
 
@@ -133,3 +133,51 @@ def test_default_host_is_localhost(temp_server_root):
         root_password=TEST_PASSWORD,
     )
     assert server.get_studio_url().startswith("http://localhost:")
+
+
+@pytest.mark.server
+@pytest.mark.skipif(not has_server_support(), reason="Requires server support")
+def test_failed_server_start_does_not_hang_process_exit(tmp_path):
+    """A server.start() that fails part-way must not leave the process unable to exit.
+
+    Regression: when a plugin fails to start, the engine has already started
+    non-daemon threads (the HTTP idempotency cleaner, the security and session
+    timers) and only the Java stop() ends them. The wrapper's stop() returned
+    early because the start never completed, so the process hung at exit (a CI
+    job ran 28 minutes past its tests on 2026-10-02). The failure is forced with
+    a Postgres port out of range, which fails on every OS; a busy port does not
+    (macOS lets the engine's listener bind a port another socket holds).
+    """
+    import subprocess  # nosec B404 - fixed argv, no shell
+    import sys
+
+    code = (
+        "import socket\n"
+        "from arcadedb_embedded import create_server\n"
+        "def free():\n"
+        "    with socket.socket() as s:\n"
+        "        s.bind(('127.0.0.1', 0))\n"
+        "        return s.getsockname()[1]\n"
+        "server = create_server(\n"
+        f"    root_path={str(tmp_path / 'databases')!r},\n"
+        f"    root_password={TEST_PASSWORD!r},\n"
+        "    config={\n"
+        "        'http_port': free(),\n"
+        "        'server_plugins': 'Redis:com.arcadedb.redis.RedisProtocolPlugin,'\n"
+        "                          'Postgres:com.arcadedb.postgres.PostgresProtocolPlugin',\n"
+        "        'redis_port': free(),\n"
+        "        'postgres_port': 70000,\n"
+        "    },\n"
+        ")\n"
+        "try:\n"
+        "    server.start()\n"
+        "    print('started')\n"
+        "    server.stop()\n"
+        "except Exception:\n"
+        "    print('start failed')\n"
+    )
+    proc = subprocess.run(  # nosec B603 - interpreter + inline snippet, no shell
+        [sys.executable, "-c", code], capture_output=True, text=True, timeout=120
+    )
+    assert "start failed" in proc.stdout, proc.stdout + proc.stderr
+    assert proc.returncode == 0
@@ -40,6 +40,23 @@ def _free_port():
         return s.getsockname()[1]
 
 
+def _free_ports(*names):
+    """Distinct free ports, one per name. Each socket stays bound until all are
+    chosen, so the OS cannot hand the same port out twice (one port per call,
+    closed before the next, let the Postgres plugin find its port taken on a
+    macOS runner on 2026-10-02)."""
+    socks = []
+    try:
+        for _ in names:
+            s = socket.socket()
+            s.bind(("127.0.0.1", 0))
+            socks.append(s)
+        return {n: s.getsockname()[1] for n, s in zip(names, socks)}
+    finally:
+        for s in socks:
+            s.close()
+
+
 def _wait(port, timeout=60.0):
     """Wait for a listener, then give the plugin a moment to finish binding."""
     deadline = time.time() + timeout
@@ -57,7 +74,7 @@ def wire_server(tmp_path):
     """A server with all three bundled wire plugins enabled."""
     from arcadedb_embedded import create_server
 
-    ports = {k: _free_port() for k in ("http", "postgres", "redis", "bolt")}
+    ports = _free_ports("http", "postgres", "redis", "bolt")
     server = create_server(
         root_path=str(tmp_path / "databases"),
         root_password=ROOT_PASSWORD,