diff --git a/changelog.d/1547-nominatim-cache-mode-windows.md b/changelog.d/1547-nominatim-cache-mode-windows.md
new file mode 100644
index 000000000..9a48b1ee6
--- /dev/null
+++ b/changelog.d/1547-nominatim-cache-mode-windows.md
@@ -0,0 +1,3 @@
+- The Nominatim disk-cache test checks the cache directory and file modes
+  only where POSIX modes exist, so it no longer always fails on Windows
+  (quanticsoul4772, #1547).
diff --git a/src/tooling/nominatimOutlineRoute.test.mjs b/src/tooling/nominatimOutlineRoute.test.mjs
index c29b41f21..74f0b2d6a 100644
--- a/src/tooling/nominatimOutlineRoute.test.mjs
+++ b/src/tooling/nominatimOutlineRoute.test.mjs
@@ -684,25 +684,34 @@ test('the disk cache survives a restart and stays within its bounds', async () =
     await createNominatimCache({ dir, now: time.now }).get('k0'),
     null,
   );
-  assert.equal(
-    fs.statSync(dir).mode & 0o777,
-    0o700,
-    'the query cache directory is private',
-  );
+  // The cache is private only through POSIX mode bits. Windows has none
+  // (directories stat as 0o666) and the cache keeps the checkout's ACLs,
+  // so these checks run, and privacy holds, only on POSIX systems.
+  const posixModes = process.platform !== 'win32';
+  if (posixModes) {
+    assert.equal(
+      fs.statSync(dir).mode & 0o777,
+      0o700,
+      'the query cache directory is private (POSIX modes)',
+    );
+  }
   const text = fs
     .readdirSync(dir)
     .filter((name) => name.endsWith('.json'))
     .map((name) => fs.readFileSync(path.join(dir, name), 'utf8'))
     .join('\n');
   assert.equal(text.includes('k4'), false, 'disk entries never store raw keys');
-  for (const name of fs
-    .readdirSync(dir)
-    .filter((entry) => entry.endsWith('.json')))
-    assert.equal(
-      fs.statSync(path.join(dir, name)).mode & 0o777,
-      0o600,
-      `${name} is private`,
-    );
+  if (posixModes) {
+    for (const name of fs
+      .readdirSync(dir)
+      .filter((entry) => entry.endsWith('.json'))) {
+      assert.equal(
+        fs.statSync(path.join(dir, name)).mode & 0o777,
+        0o600,
+        `${name} is private (POSIX modes)`,
+      );
+    }
+  }
   fs.rmSync(dir, { recursive: true, force: true });
 });