diff --git a/lib/ace/worker/worker_client.js b/lib/ace/worker/worker_client.js
index 7c7be791738..1bd54ffcb05 100644
--- a/lib/ace/worker/worker_client.js
+++ b/lib/ace/worker/worker_client.js
@@ -171,7 +171,7 @@ var WorkerClient = function(worker) {
             // TODO: cleanup event
             if (data.data && data.data.err)
                 data.data.err = {message: data.data.err.message, stack: data.data.err.stack, code: data.data.err.code};
-            this.$worker.postMessage({event: event, data: {data: data.data}});
+                this.$worker && this.$worker.postMessage({event: event, data: {data: data.data}});
         }
         catch(ex) {
             console.error(ex.stack);