diff --git a/toolkit/mozapps/downloads/DownloadUtils.jsm b/toolkit/mozapps/downloads/DownloadUtils.jsm
index 60fc6e0285..df74b4605f 100644
--- a/toolkit/mozapps/downloads/DownloadUtils.jsm
+++ b/toolkit/mozapps/downloads/DownloadUtils.jsm
@@ -497,16 +497,14 @@ this.DownloadUtils = {
     // Don't try to format Infinity values using NumberFormat.
     if (aBytes === Infinity) {
       aBytes = "Infinity";
+    } else if (typeof Intl != "undefined") {
+      aBytes = getLocaleNumberFormat(fractionDigits)
+                 .format(aBytes);
     } else {
-      try {
-        aBytes = getLocaleNumberFormat(fractionDigits)
-                   .format(aBytes);
-      } catch(e) {
-        // FIXME: Fall back to the old hack, will be fixed in bug 1200494.
-        aBytes = aBytes.toFixed(fractionDigits);
-        if (gDecimalSymbol != ".") {
-          aBytes = aBytes.replace(".", gDecimalSymbol);
-        }
+      // FIXME: Fall back to the old hack, will be fixed in bug 1200494.
+      aBytes = aBytes.toFixed(fractionDigits);
+      if (gDecimalSymbol != ".") {
+        aBytes = aBytes.replace(".", gDecimalSymbol);
       }
     }