diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
index e35af4e291a70..f03cdf343024d 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
@@ -102,12 +102,6 @@ class NativeSessionStorage implements SessionStorageInterface
      */
     public function __construct(array $options = array(), $handler = null, MetadataBag $metaBag = null)
     {
-        $this->setMetadataBag($metaBag);
-
-        if (\PHP_VERSION_ID >= 50400 && \PHP_SESSION_ACTIVE === session_status()) {
-            return;
-        }
-
         $options += array(
             // disable by default because it's managed by HeaderBag (if used)
             'cache_limiter' => '',
@@ -120,6 +114,7 @@ public function __construct(array $options = array(), $handler = null, MetadataB
             register_shutdown_function('session_write_close');
         }
 
+        $this->setMetadataBag($metaBag);
         $this->setOptions($options);
         $this->setSaveHandler($handler);
     }
@@ -292,7 +287,7 @@ public function getBag($name)
             throw new \InvalidArgumentException(sprintf('The SessionBagInterface %s is not registered.', $name));
         }
 
-        if ($this->saveHandler->isActive() && !$this->started) {
+        if (!$this->started && $this->saveHandler->isActive()) {
             $this->loadSession();
         } elseif (!$this->started) {
             $this->start();
@@ -340,7 +335,7 @@ public function isStarted()
      */
     public function setOptions(array $options)
     {
-        if (headers_sent()) {
+        if (headers_sent() || (\PHP_VERSION_ID >= 50400 && \PHP_SESSION_ACTIVE === session_status())) {
             return;
         }
 
@@ -395,10 +390,6 @@ public function setSaveHandler($saveHandler = null)
             throw new \InvalidArgumentException('Must be instance of AbstractProxy or NativeSessionHandler; implement \SessionHandlerInterface; or be null.');
         }
 
-        if (headers_sent($file, $line)) {
-            throw new \RuntimeException(sprintf('Failed to set the session handler because headers have already been sent by "%s" at line %d.', $file, $line));
-        }
-
         // Wrap $saveHandler in proxy and prevent double wrapping of proxy
         if (!$saveHandler instanceof AbstractProxy && $saveHandler instanceof \SessionHandlerInterface) {
             $saveHandler = new SessionHandlerProxy($saveHandler);
@@ -408,6 +399,10 @@ public function setSaveHandler($saveHandler = null)
         }
         $this->saveHandler = $saveHandler;
 
+        if (headers_sent() || (\PHP_VERSION_ID >= 50400 && \PHP_SESSION_ACTIVE === session_status())) {
+            return;
+        }
+
         if ($this->saveHandler instanceof \SessionHandlerInterface) {
             if (\PHP_VERSION_ID >= 50400) {
                 session_set_save_handler($this->saveHandler, false);
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
index 673cd386bf6aa..7eb7e56478ce5 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
@@ -296,4 +296,19 @@ public function testSetSessionOptionsOnceSessionStartedIsIgnored()
         // Assert no exception has been thrown by `getStorage()`
         $this->addToAssertionCount(1);
     }
+
+    /**
+     * @requires PHP 5.4
+     */
+    public function testGetBagsOnceSessionStartedIsIgnored()
+    {
+        session_start();
+        $bag = new AttributeBag();
+        $bag->setName('flashes');
+
+        $storage = $this->getStorage();
+        $storage->registerBag($bag);
+
+        $this->assertEquals($storage->getBag('flashes'), $bag);
+    }
 }