diff --git a/core/email.class.inc.php b/core/email.class.inc.php
index 8ff27211b..7eb528fa1 100644
--- a/core/email.class.inc.php
+++ b/core/email.class.inc.php
@@ -321,6 +321,11 @@ class EMail
 	public function GetRecipientTO($bAsString = false)
 	{
 		$aRes = $this->m_oMessage->getTo();
+		if ($aRes === false)
+		{
+			// There is no "To" header field
+			$aRes = array();
+		}
 		if ($bAsString)
 		{
 			$aStrings = array();
diff --git a/lib/swiftmailer/lib/classes/Swift/Mime/SimpleMimeEntity.php b/lib/swiftmailer/lib/classes/Swift/Mime/SimpleMimeEntity.php
index e2fc7296d..ad34612bb 100644
--- a/lib/swiftmailer/lib/classes/Swift/Mime/SimpleMimeEntity.php
+++ b/lib/swiftmailer/lib/classes/Swift/Mime/SimpleMimeEntity.php
@@ -595,6 +595,7 @@ class Swift_Mime_SimpleMimeEntity implements Swift_Mime_MimeEntity
         if ($this->_headers->has($field)) {
             return $this->_headers->get($field)->getFieldBodyModel();
         }
+        return false;
     }
 
     /**