--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -4930,20 +4930,22 @@ MultiprocessBlockPolicy() {
     }
   }
 #endif
 
   /**
    * Avoids enabling e10s for Windows XP users on the release channel.
    */
 #if defined(XP_WIN)
-  if (Preferences::GetDefaultCString("app.update.channel").EqualsLiteral("release") &&
-      !IsVistaOrLater()) {
-    gMultiprocessBlockPolicy = kE10sDisabledForOperatingSystem;
-    return gMultiprocessBlockPolicy;
+  if (!IsVistaOrLater()) {
+    nsAdoptingCString channelName = Preferences::GetDefaultCString("app.update.channel");
+    if (channelName.EqualsLiteral("release") || channelName.EqualsLiteral("esr")) {
+      gMultiprocessBlockPolicy = kE10sDisabledForOperatingSystem;
+      return gMultiprocessBlockPolicy;
+    }
   }
 #endif // XP_WIN
 
   /*
    * None of the blocking policies matched, so e10s is allowed to run.
    * Cache the information and return 0, indicating success.
    */
   gMultiprocessBlockPolicy = 0;