--- a/devtools/shared/webconsole/network-monitor.js
+++ b/devtools/shared/webconsole/network-monitor.js
@@ -518,16 +518,21 @@ NetworkResponseListener.prototype = {
 
   /**
    * Handle the onStopRequest by closing the sink output stream.
    *
    * For more documentation about nsIRequestObserver go to:
    * https://developer.mozilla.org/En/NsIRequestObserver
    */
   onStopRequest: function () {
+    // Bug 1429365: onStopRequest may be called after onComplete for resources loaded
+    // from bytecode cache.
+    if (!this.httpActivity) {
+      return;
+    }
     this._findOpenResponse();
     this.sink.outputStream.close();
   },
 
   // nsIProgressEventSink implementation
 
   /**
    * Handle progress event as data is transferred.  This is used to record the