diff --git a/src/viur/core/bones/file.py b/src/viur/core/bones/file.py
index dfe312069..c1139d0d7 100644
--- a/src/viur/core/bones/file.py
+++ b/src/viur/core/bones/file.py
@@ -214,7 +214,7 @@ def postSavedHandler(self, skel, boneName, key):
         def handleDerives(values):
             if isinstance(values, dict):
                 values = [values]
-            for val in values:  # Ensure derives getting build for each file referenced in this relation
+            for val in (values or ()):  # Ensure derives getting build for each file referenced in this relation
                 ensureDerived(val["dest"]["key"], f"{skel.kindName}_{boneName}", self.derive)
 
         values = skel[boneName]