diff --git a/mailsystem.module b/mailsystem.module
index e414280..49ac7fc 100644
--- a/mailsystem.module
+++ b/mailsystem.module
@@ -302,7 +302,10 @@ function &mailsystem_get_classes() {
           ->execute();
       }
     }
-    foreach (array_unique(mailsystem_get()) as $classname) {
+
+    $current_classes = array_unique(mailsystem_get());
+    unset($current_classes['mailsystem_theme']);
+    foreach ($current_classes as $classname) {
       if (class_exists($classname)) {
         $mailsystem_classes[$classname] = $classname;
       }