diff --git a/migrate_ui/migrate_ui.pages.inc b/migrate_ui/migrate_ui.pages.inc
index 312eed5..338c831 100644
--- a/migrate_ui/migrate_ui.pages.inc
+++ b/migrate_ui/migrate_ui.pages.inc
@@ -1056,9 +1056,12 @@ function migrate_ui_edit_mappings($form, $form_state, $group_name,
       );
     }
 
+    if(isset($field_mappings[is_new])) {
+      $deftault_is_new = $field_mappings[is_new]->getDefaultValue();
+    }
     foreach ($dest_fields as $name => $description) {
-      // Don't map the destination key
-      if (isset($dest_key[$name])) {
+      // Don't map the destination key unless is_new = TRUE
+      if (isset($dest_key[$name]) && $deftault_is_new <> 1) {
         continue;
       }