diff -u b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
--- b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
@@ -107,6 +107,8 @@
       'poll',
       'profile',
       'rdf',
+      'simpletest',
+      'syslog',
       'tracker',
       'trigger',
       'toolbar',