diff --git a/product/ERP5/mixin/cached_convertable.py b/product/ERP5/mixin/cached_convertable.py
index 48b7769f543fc7d0c848770e110cf7eaa3eba848..0c2a0f75998b009dbabc67b5d318bce686b84319 100644
--- a/product/ERP5/mixin/cached_convertable.py
+++ b/product/ERP5/mixin/cached_convertable.py
@@ -178,4 +178,6 @@ class CachedConvertableMixin:
               it general or related to caching only ?
     """
     data = self.getData()
-    self._setContentMd5(md5.new(data).hexdigest()) # Reindex is useless
+    if data is not None:
+      data = str(data) # Usefull for Pdata
+      self._setContentMd5(md5.new(data).hexdigest()) # Reindex is useless