--- a/testing/marionette/components/marionette.js
+++ b/testing/marionette/components/marionette.js
@@ -444,16 +444,17 @@ class MarionetteMainProcess {
         const {TCPListener} = ChromeUtils.import("chrome://marionette/content/server.js", {});
         let listener = new TCPListener(MarionettePrefs.port);
         listener.start();
         this.server = listener;
       } catch (e) {
         log.fatal("Remote protocol server failed to start", e);
         this.uninit();
         Services.startup.quit(Ci.nsIAppStartup.eForceQuit);
+        return;
       }
 
       env.set(ENV_ENABLED, "1");
       Services.obs.notifyObservers(this, NOTIFY_RUNNING, true);
       log.debug("Remote service is active");
     });
   }