diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19cae84..4d9e447 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,12 @@ here. Native format compatibility is documented separately in
 
 ## Unreleased
 
+- Fix `catalog refresh` reporting every root as `scan_failed` on Windows
+  volumes whose serial number (or file ID) exceeds `2**63 - 1`. Python reports
+  `st_dev`/`st_ino` there as unsigned 64-bit values, which SQLite rejected with
+  `OverflowError`; they are now folded into the signed INTEGER range before
+  being stored or compared.
+
 ## 0.12.0 - 2026-10-19
 
 - Fix atomic writes on Windows in `write_private_atomic`: skip the Unix-only
diff --git a/src/session_migrate/catalog.py b/src/session_migrate/catalog.py
index 95269ec..b6b328d 100644
--- a/src/session_migrate/catalog.py
+++ b/src/session_migrate/catalog.py
@@ -1175,8 +1175,8 @@ def _refresh_root(self, root: CatalogRoot, *, validate: bool) -> dict[str, int]:
                 unchanged = bool(
                     previous
                     and previous["status"] != "missing"
-                    and int(previous["device"]) == before.device
-                    and int(previous["inode"]) == before.inode
+                    and int(previous["device"]) == _sqlite_int(before.device)
+                    and int(previous["inode"]) == _sqlite_int(before.inode)
                     and int(previous["bytes"]) == before.size
                     and int(previous["modified_ns"]) == before.modified_ns
                     and previous["source_fingerprint"] == getattr(before, "fingerprint", None)
@@ -1544,8 +1544,8 @@ def _upsert_session(
                 scan.status,
                 scan.reason,
                 scan.records,
-                snapshot.device,
-                snapshot.inode,
+                _sqlite_int(snapshot.device),
+                _sqlite_int(snapshot.inode),
                 snapshot.size,
                 snapshot.modified_ns,
                 getattr(snapshot, "fingerprint", None),
@@ -1625,8 +1625,8 @@ def _upsert_virtual_session(
                 scan.status,
                 scan.reason,
                 scan.records,
-                snapshot.device,
-                snapshot.inode,
+                _sqlite_int(snapshot.device),
+                _sqlite_int(snapshot.inode),
                 snapshot.size,
                 snapshot.modified_ns,
                 snapshot.fingerprint,
@@ -3107,6 +3107,17 @@ def _is_non_negative_sqlite_int(value: Any) -> bool:
     return isinstance(value, int) and not isinstance(value, bool) and value >= 0
 
 
+def _sqlite_int(value: int) -> int:
+    """Fold an unsigned 64-bit stat identity into SQLite's signed INTEGER range.
+
+    Windows reports st_dev (volume serial) and st_ino (file ID) as unsigned
+    64-bit values, which SQLite rejects with OverflowError above 2**63 - 1.
+    """
+
+    value &= (1 << 64) - 1
+    return value - (1 << 64) if value >= 1 << 63 else value
+
+
 def _copilot_native_metadata(root: Path) -> _NativeMetadata:
     """Read only bounded picker names, never event/message content."""
 
diff --git a/tests/test_catalog.py b/tests/test_catalog.py
index 9da67b1..d60c760 100644
--- a/tests/test_catalog.py
+++ b/tests/test_catalog.py
@@ -7,6 +7,7 @@
 import pytest
 
 import session_migrate.catalog as catalog_module
+import session_migrate.jsonl as jsonl_module
 from session_migrate.catalog import Catalog, auto_roots, default_catalog_path, discover_roots
 from session_migrate.errors import JsonlError, SessionMigrateError
 from session_migrate.formats import (
@@ -463,6 +464,38 @@ def test_refresh_is_incremental_and_validation_is_explicit(tmp_path: Path) -> No
         assert catalog.list_sessions()[0].reason is None
 
 
+def test_refresh_stores_unsigned_64_bit_stat_identities(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    # Windows reports st_dev/st_ino as unsigned 64-bit values that can exceed
+    # SQLite's signed INTEGER range.
+    home = tmp_path / "claude"
+    session = home / "projects" / "-synthetic" / f"{CLAUDE_ID}.jsonl"
+    _write_jsonl(session, _claude_records(CLAUDE_ID, "Unsigned identity"))
+    real_snapshot = jsonl_module.file_snapshot
+
+    def unsigned_snapshot(path: Path) -> jsonl_module.FileSnapshot:
+        snapshot = real_snapshot(path)
+        return jsonl_module.FileSnapshot(
+            device=2**64 - 1,
+            inode=2**63 + 7,
+            size=snapshot.size,
+            modified_ns=snapshot.modified_ns,
+        )
+
+    monkeypatch.setattr(catalog_module, "file_snapshot", unsigned_snapshot)
+    monkeypatch.setattr(jsonl_module, "file_snapshot", unsigned_snapshot)
+
+    with _catalog(tmp_path) as catalog:
+        first = catalog.refresh(claude_roots=(home,), include_auto=False)
+        assert first.root_errors == 0
+        assert first.scanned == 1
+        second = catalog.refresh(include_auto=False)
+        assert second.root_errors == 0
+        assert second.scanned == 0
+        assert second.unchanged == 1
+
+
 def test_pi_sessions_are_named_searchable_validatable_and_version_guarded(
     tmp_path: Path,
 ) -> None: