diff --git a/lemur/common/managers.py b/lemur/common/managers.py
index 4e693677..79f4cb1d 100644
--- a/lemur/common/managers.py
+++ b/lemur/common/managers.py
@@ -22,7 +22,8 @@ class InstanceManager(object):
 
     def add(self, class_path):
         self.cache = None
-        self.class_list.append(class_path)
+        if class_path not in self.class_list:
+            self.class_list.append(class_path)
 
     def remove(self, class_path):
         self.cache = None
diff --git a/lemur/plugins/views.py b/lemur/plugins/views.py
index ddbe780e..d2dd606a 100644
--- a/lemur/plugins/views.py
+++ b/lemur/plugins/views.py
@@ -86,7 +86,7 @@ class PluginsList(AuthenticatedResource):
         if args['type']:
             return list(plugins.all(plugin_type=args['type']))
 
-        return plugins.all()
+        return list(plugins.all())
 
 
 class Plugins(AuthenticatedResource):