diff --git a/gateway/hosted_room_policy_checkpoint.py b/gateway/hosted_room_policy_checkpoint.py
index 2d79bc98aa..f4e9adb822 100644
--- a/gateway/hosted_room_policy_checkpoint.py
+++ b/gateway/hosted_room_policy_checkpoint.py
@@ -114,7 +114,7 @@ class HostedRoomPolicyCheckpoint:
         self.db_path.parent.mkdir(parents=True, exist_ok=True)
         conn = sqlite3.connect(self.db_path, timeout=10)
         conn.row_factory = sqlite3.Row
-        apply_wal_with_fallback(conn, db_label="state.db (room policy checkpoint)")
+        apply_wal_with_fallback(conn, db_label="shared-state.db (room policy checkpoint)")
         return conn
 
     @staticmethod
diff --git a/gateway/hosted_rooms.py b/gateway/hosted_rooms.py
index ba9be1b7d6..7874243db2 100644
--- a/gateway/hosted_rooms.py
+++ b/gateway/hosted_rooms.py
@@ -423,7 +423,7 @@ def local_authority_gateway_id() -> str:
 
 
 _connect = partial(
-    connect, db_label="state.db (hosted_rooms)", ready=_schema_is_current,
+    connect, db_label="shared-state.db (hosted_rooms)", ready=_schema_is_current,
     initialize=lambda conn: _initialize_schema(conn), lock_retries=_JOURNAL_MODE_LOCK_RETRIES)
 
 
diff --git a/tests/gateway/test_hosted_rooms.py b/tests/gateway/test_hosted_rooms.py
index 65c2272423..64a1cc5773 100644
--- a/tests/gateway/test_hosted_rooms.py
+++ b/tests/gateway/test_hosted_rooms.py
@@ -1339,3 +1339,26 @@ def test_room_log_page_bound_counts_bytes_not_characters(tmp_path, monkeypatch):
     assert [event["seq"] for event in page["events"]] == [1]
     assert page_bytes(page) <= budget
     assert page["has_more"] is True
+
+
+def test_default_db_path_never_names_the_master_session_store(tmp_path, monkeypatch):
+    """Hosted-room coordination lives beside, never inside, the master ``state.db``.
+
+    Every profile gateway starts the hosted-room worker, so a store resolved to the
+    root session DB made every profile process a long-lived writer on state.db —
+    the multi-profile restart corruption in #102120 / #103339 / #103490. The store
+    is shared across profiles (one file at the install root) but is not the
+    SessionDB file the root gateway owns.
+    """
+    root = tmp_path / ".hermes"
+    profile_home = root / "profiles" / "bot1"
+    profile_home.mkdir(parents=True)
+
+    monkeypatch.setenv("HERMES_HOME", str(profile_home))
+    from_profile = rooms.default_db_path()
+    monkeypatch.setenv("HERMES_HOME", str(root))
+    from_root = rooms.default_db_path()
+
+    assert from_profile == from_root, "one coordination file per install"
+    assert from_root.parent == root
+    assert from_root.name != "state.db"
diff --git a/tests/tui_gateway/test_groups_methods.py b/tests/tui_gateway/test_groups_methods.py
index 4ab00cdaba..54e6635609 100644
--- a/tests/tui_gateway/test_groups_methods.py
+++ b/tests/tui_gateway/test_groups_methods.py
@@ -6,6 +6,7 @@ from types import SimpleNamespace
 
 import pytest
 
+from gateway.hosted_rooms import default_db_path as hosted_rooms_default_db_path
 import tui_gateway.server as srv
 from tui_gateway import methods_groups
 
@@ -346,7 +347,7 @@ def test_register_peer_route_probes_scope_and_persists_via_service(home, monkeyp
             }
 
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
         def register_peer_route(self, **kwargs):
             captured["registered"] = kwargs
@@ -376,7 +377,7 @@ def test_register_peer_route_probes_scope_and_persists_via_service(home, monkeyp
 
 def test_register_rejects_plaintext_non_loopback(home, monkeypatch):
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
     monkeypatch.setattr(srv, "get_hosted_room_service", lambda: FakeService())
     response = srv._methods["groups.peer.register"](
@@ -398,7 +399,7 @@ def test_register_requires_roomlink_protocol_v2(home, monkeypatch):
     from gateway.hosted_room_peer import catalog_mapping
 
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
     monkeypatch.setattr(srv, "get_hosted_room_service", lambda: FakeService())
     response = srv._methods["groups.peer.register"](
@@ -914,7 +915,7 @@ def test_disband_stops_and_revokes_before_tombstoning(home, monkeypatch):
     calls = []
 
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
         def stop_room(self, room_id, **_kwargs):
             calls.append(("stop", room_id))
@@ -933,7 +934,7 @@ def test_failed_remote_revocation_keeps_room_recoverable(home, monkeypatch):
     _create_room()
 
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
         def stop_room(self, _room_id, **_kwargs):
             return 1
@@ -958,7 +959,7 @@ def test_disband_does_not_revoke_routes_while_stop_is_unacknowledged(
     calls = []
 
     class FakeService:
-        db_path = home / "state.db"
+        db_path = hosted_rooms_default_db_path()
 
         def stop_room(self, _room_id, **kwargs):
             calls.append(("stop", kwargs["require_acknowledged"]))