diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 6e271d5..7eebe66 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -996,7 +996,10 @@ function install_base_system(&$install_state) {
   // created by this point in the installer, since Drupal creates them during
   // the install_verify_requirements() task. Note that we cannot call
   // file_ensure_access() any earlier than this, since it relies on
-  // system.module in order to work.
+  // system.module in order to work. Flush stream wrapper plugins to make sure
+  // that we correctly discovered all stream wrapper plugins.
+  \Drupal::service('plugin.manager.stream_wrapper')->clearCachedDefinitions();
+  file_get_stream_wrappers();
   file_ensure_htaccess();
 
   // Enable the user module so that sessions can be recorded during the
diff --git a/core/modules/system/lib/Drupal/system/Form/FileSystemForm.php b/core/modules/system/lib/Drupal/system/Form/FileSystemForm.php
index d9cc47c..fad6b81 100644
--- a/core/modules/system/lib/Drupal/system/Form/FileSystemForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/FileSystemForm.php
@@ -124,6 +124,12 @@ public function submitForm(array &$form, array &$form_state) {
     $config->save();
 
     parent::submitForm($form, $form_state);
+
+    // Private stream wrapper will be hidden until path.pravte configuration
+    // value is set. Since we cache plugin information about stream wrappers we
+    // need to clear it's cache in case path.private was initially set on this
+    // submit.
+    \Drupal::service('plugin.manager.stream_wrapper')->clearCachedDefinitions();
   }
 
 }