diff --git a/toolkit/content/aboutTelemetry.js b/toolkit/content/aboutTelemetry.js
index 063c6fa8c09a..87ac04d3fd85 100644
--- a/toolkit/content/aboutTelemetry.js
+++ b/toolkit/content/aboutTelemetry.js
@@ -814,7 +814,9 @@ let KeyValueTable = {
   renderBody: function KeyValueTable_renderBody(aTable, aMeasurements) {
     for (let [key, value] of Iterator(aMeasurements)) {
       // use .valueOf() to unbox Number, String, etc. objects
-      if ((typeof value == "object") && (typeof value.valueOf() == "object")) {
+      if (value &&
+         (typeof value == "object") &&
+         (typeof value.valueOf() == "object")) {
         value = RenderObject(value);
       }