--- a/testing/marionette/components/marionette.js
+++ b/testing/marionette/components/marionette.js
@@ -111,29 +111,33 @@ const prefs = {
           Preferences.set(prefName, prefs[prefName]);
         }
       }
     }
   },
 };
 
 function MarionetteComponent() {
-  this.enabled = env.exists(ENV_ENABLED);
   this.running = false;
   this.server = null;
 
   // holds reference to ChromeWindow
   // used to run GFX sanity tests on Windows
   this.gfxWindow = null;
 
   // indicates that all pending window checks have been completed
   // and that we are ready to start the Marionette server
   this.finalUIStartup = false;
 
   this.logger = this.setupLogger(prefs.logLevel);
+
+  this.enabled = env.exists(ENV_ENABLED);
+  if (this.enabled) {
+    this.logger.info(`Enabled via ${ENV_ENABLED}`);
+  }
 }
 
 MarionetteComponent.prototype = {
   classDescription: "Marionette component",
   classID: MARIONETTE_CID,
   contractID: MARIONETTE_CONTRACT_ID,
   QueryInterface: XPCOMUtils.generateQI([
     Ci.nsICommandLineHandler,
@@ -143,18 +147,19 @@ MarionetteComponent.prototype = {
     {category: "command-line-handler", entry: "b-marionette"},
     {category: "profile-after-change", service: true},
   ],
   helpInfo: "  --marionette       Enable remote control server.\n",
 };
 
 // Handle -marionette flag
 MarionetteComponent.prototype.handle = function(cmdLine) {
-  if (cmdLine.handleFlag("marionette", false)) {
+  if (!this.enabled && cmdLine.handleFlag("marionette", false)) {
     this.enabled = true;
+    this.logger.info("Enabled via --marionette");
   }
 };
 
 MarionetteComponent.prototype.observe = function(subject, topic, data) {
   switch (topic) {
     case "command-line-startup":
       Services.obs.removeObserver(this, topic);
       this.handle(subject);