diff --git a/src/calibre/gui2/preferences/create_custom_column.py b/src/calibre/gui2/preferences/create_custom_column.py
index ed5e7d9cc6..8c62aed5eb 100644
--- a/src/calibre/gui2/preferences/create_custom_column.py
+++ b/src/calibre/gui2/preferences/create_custom_column.py
@@ -543,6 +543,8 @@ class CreateCustomColumn(QDialog):
 
         default_val = (unicode_type(self.default_value.text()).strip()
                         if col_type != 'composite' else None)
+        if self.editing_col:
+            self.parent.custcols[self.orig_column_name]['display'].pop('default_value', None)
 
         if col_type == 'datetime':
             if unicode_type(self.format_box.text()).strip():