diff --git a/src/openjarvis/server/session_store.py b/src/openjarvis/server/session_store.py
index 107f0052..7dd829cd 100644
--- a/src/openjarvis/server/session_store.py
+++ b/src/openjarvis/server/session_store.py
@@ -25,9 +25,11 @@ class SessionStore:
     def __init__(self, db_path: str = "") -> None:
         if not db_path:
             db_path = str(get_config_dir() / "sessions.db")
-        from openjarvis.security.file_utils import secure_create
+        # Ensure the parent directory exists (skip for :memory:)
+        if db_path != ":memory:":
+            from openjarvis.security.file_utils import secure_create
 
-        secure_create(Path(db_path))
+            secure_create(Path(db_path))
         self._db = sqlite3.connect(db_path, check_same_thread=False)
         self._db.row_factory = sqlite3.Row
         self._create_tables()
diff --git a/tests/server/test_session_store.py b/tests/server/test_session_store.py
index c078b25e..6f637035 100644
--- a/tests/server/test_session_store.py
+++ b/tests/server/test_session_store.py
@@ -115,3 +115,29 @@ class TestLastActiveChannel:
 
     def test_returns_none_for_unknown_user(self, store):
         assert store.get_last_active_channel("nobody") is None
+
+
+class TestInMemoryDatabase:
+    """``:memory:`` is a SQLite sentinel, not a path — it must not be created.
+
+    ``secure_create`` treats it as a filename, which fails outright on Windows
+    (``:`` is illegal there) and litters the working directory elsewhere.
+    """
+
+    def test_in_memory_store_is_usable(self):
+        s = SessionStore(db_path=":memory:")
+        try:
+            session = s.get_or_create("user1", "twilio")
+            assert session["sender_id"] == "user1"
+        finally:
+            s.close()
+
+    def test_in_memory_store_creates_no_file(self, tmp_path, monkeypatch):
+        monkeypatch.chdir(tmp_path)
+        before = set(tmp_path.iterdir())
+        s = SessionStore(db_path=":memory:")
+        try:
+            assert set(tmp_path.iterdir()) == before
+            assert not (tmp_path / ":memory:").exists()
+        finally:
+            s.close()