diff --git a/loopx/control_plane/work_items/operator_inbox.py b/loopx/control_plane/work_items/operator_inbox.py
index aba79c90e5..07efb76a0d 100644
--- a/loopx/control_plane/work_items/operator_inbox.py
+++ b/loopx/control_plane/work_items/operator_inbox.py
@@ -63,8 +63,11 @@ def _pending_events(
 ) -> list[dict[str, Any]]:
     processed_path = inbox / "processed.json"
     processed: set[str] = set()
-    if processed_path.is_file():
+    try:
         processed_payload = _read_mapping(processed_path)
+    except FileNotFoundError:
+        pass
+    else:
         if (
             processed_payload.get("schema_version")
             != source_contract.processed_schema_version
diff --git a/loopx/extensions/lark/event_inbox.py b/loopx/extensions/lark/event_inbox.py
index 3f8a429d52..453d78e1ae 100644
--- a/loopx/extensions/lark/event_inbox.py
+++ b/loopx/extensions/lark/event_inbox.py
@@ -239,9 +239,10 @@ def load_lark_event_inbox_config(
 
 
 def _load_processed(path: Path) -> set[str]:
-    if not path.is_file():
+    try:
+        payload = json.loads(path.read_text(encoding="utf-8"))
+    except FileNotFoundError:
         return set()
-    payload = json.loads(path.read_text(encoding="utf-8"))
     if (
         not isinstance(payload, Mapping)
         or payload.get("schema_version") != PROCESSED_SCHEMA_VERSION
@@ -726,12 +727,13 @@ def inspect_lark_event_inbox(
 
 def _material_review_ledger(inbox: Path) -> tuple[Path, dict[str, Any]]:
     path = inbox / "material-review" / "receipts.json"
-    if not path.is_file():
+    try:
+        payload = json.loads(path.read_text(encoding="utf-8"))
+    except FileNotFoundError:
         return path, {
             "schema_version": MATERIAL_REVIEW_LEDGER_SCHEMA_VERSION,
             "receipts": {},
         }
-    payload = json.loads(path.read_text(encoding="utf-8"))
     if (
         not isinstance(payload, dict)
         or payload.get("schema_version") != MATERIAL_REVIEW_LEDGER_SCHEMA_VERSION
diff --git a/tests/extensions/test_operator_inbox_material_review.py b/tests/extensions/test_operator_inbox_material_review.py
index c5501f9aae..2d05c8ea05 100644
--- a/tests/extensions/test_operator_inbox_material_review.py
+++ b/tests/extensions/test_operator_inbox_material_review.py
@@ -537,3 +537,56 @@ def blocked_writer(path: Path, payload: object) -> None:
     inbox = tmp_path / ".loopx" / "inbox" / "lark" / "material-review"
     processed = json.loads((inbox / "processed.json").read_text(encoding="utf-8"))
     assert set(processed["message_ids"]) == {"om_material_text", "om_direct"}
+
+
+def test_processed_state_path_damage_never_reopens_acknowledged_events(
+    tmp_path: Path,
+) -> None:
+    config = _config(tmp_path)
+    _ingest(tmp_path, config)
+    acknowledge_lark_event_inbox(
+        project=tmp_path,
+        config_path=config,
+        message_ids=["om_direct"],
+        execute=True,
+    )
+    inbox = tmp_path / ".loopx" / "inbox" / "lark" / "material-review"
+    processed = inbox / "processed.json"
+    processed.unlink()
+    processed.mkdir()
+
+    with pytest.raises(IsADirectoryError):
+        inspect_lark_event_inbox(project=tmp_path, config_path=config)
+    with pytest.raises(IsADirectoryError):
+        project_lark_event_inbox_urgency(project=tmp_path, config_path=config)
+    with pytest.raises(IsADirectoryError):
+        acknowledge_lark_event_inbox(
+            project=tmp_path,
+            config_path=config,
+            message_ids=["om_direct"],
+        )
+
+
+def test_material_review_receipt_path_damage_is_not_an_empty_ledger(
+    tmp_path: Path,
+) -> None:
+    config = _config(tmp_path)
+    _ingest(tmp_path, config)
+    receipts = (
+        tmp_path
+        / ".loopx"
+        / "inbox"
+        / "lark"
+        / "material-review"
+        / "material-review"
+        / "receipts.json"
+    )
+    receipts.mkdir(parents=True)
+
+    with pytest.raises(IsADirectoryError):
+        settle_lark_event_inbox_material_review(
+            project=tmp_path,
+            config_path=config,
+            message_id="om_material_text",
+            no_follow_up_reason="Reviewed before ledger damage.",
+        )