diff --git a/src/SessionManager.php b/src/SessionManager.php
index bf779907..26690512 100644
--- a/src/SessionManager.php
+++ b/src/SessionManager.php
@@ -93,7 +93,10 @@ public function start($preserveStorage = false)
             $this->registerSaveHandler($saveHandler);
         }
 
-        $oldSessionData = $_SESSION;
+        $oldSessionData = array();
+        if (isset($_SESSION)) {
+            $oldSessionData = $_SESSION;
+        }
 
         session_start();
 
diff --git a/test/Service/SessionManagerFactoryTest.php b/test/Service/SessionManagerFactoryTest.php
index fee441ba..5a2fc0c8 100644
--- a/test/Service/SessionManagerFactoryTest.php
+++ b/test/Service/SessionManagerFactoryTest.php
@@ -87,4 +87,18 @@ public function testFactoryWillAddValidatorViaConfiguration()
 
         $this->assertEquals(1, $manager->getValidatorChain()->getListeners('session.validate')->count());
     }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testStartingSessionManagerFromFactoryDoesNotTriggerUndefinedVariable()
+    {
+        $storage = new ArrayStorage();
+        $this->services->setService('Zend\Session\Storage\StorageInterface', $storage);
+
+        $manager = $this->services->get('Zend\Session\ManagerInterface');
+        $manager->start();
+
+        $this->assertSame($storage, $manager->getStorage());
+    }
 }