diff --git a/src/pfwbged/folder/folder.py b/src/pfwbged/folder/folder.py
index 810d8f2..c2c2e11 100644
--- a/src/pfwbged/folder/folder.py
+++ b/src/pfwbged/folder/folder.py
@@ -89,7 +89,8 @@ class Folder(Container):
         for id, item in self.contentItems():
             if not ILink.providedBy(item):
                 continue
-            parents.append(item.folder.to_object)
+            if item.folder.to_object:
+                parents.append(item.folder.to_object)
         return parents
 
     def child_folders_brains(self):