diff --git a/lib/web.js b/lib/web.js
index 3cf942ab..04e4466c 100644
--- a/lib/web.js
+++ b/lib/web.js
@@ -52,7 +52,7 @@ export const doNotTrack = () => {
     window.doNotTrack ||
     navigator.doNotTrack ||
     navigator.msDoNotTrack ||
-    'msTrackingProtectionEnabled' in window.external
+    (window.external && 'msTrackingProtectionEnabled' in window.external)
   ) {
     if (
       window.doNotTrack == '1' ||