diff --git a/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php b/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
index 6b9481a08b9d..57f628ca6d91 100644
--- a/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
+++ b/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
@@ -227,7 +227,7 @@ public function toolbarAction(Request $request, $token)
 
         $session = $request->getSession();
 
-        if (null !== $session && $session->getFlashBag() instanceof AutoExpireFlashBag) {
+        if (null !== $session && $session->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
             // keep current flashes for one more request if using AutoExpireFlashBag
             $session->getFlashBag()->setAll($session->getFlashBag()->peekAll());
         }
diff --git a/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php b/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
index 1e0f691c9674..8835e9d98e65 100644
--- a/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
+++ b/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
@@ -67,7 +67,7 @@ public function onKernelResponse(FilterResponseEvent $event)
 
         if ($response->headers->has('X-Debug-Token') && $response->isRedirect() && $this->interceptRedirects) {
             $session = $request->getSession();
-            if ($session && $session->getFlashBag() instanceof AutoExpireFlashBag) {
+            if (null !== $session && $session->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
                 // keep current flashes for one more request if using AutoExpireFlashBag
                 $session->getFlashBag()->setAll($session->getFlashBag()->peekAll());
             }