diff --git a/core/modules/simpletest/src/BrowserTestBase.php b/core/modules/simpletest/src/BrowserTestBase.php
index 822e432..ad0a18e 100644
--- a/core/modules/simpletest/src/BrowserTestBase.php
+++ b/core/modules/simpletest/src/BrowserTestBase.php
@@ -929,9 +929,13 @@ public function installDrupal() {
     file_prepare_directory($this->privateFilesDirectory, FILE_CREATE_DIRECTORY);
     file_prepare_directory($this->tempFilesDirectory, FILE_CREATE_DIRECTORY);
     $config->getEditable('system.file')
-      ->set('path.private', $this->privateFilesDirectory)
       ->set('path.temporary', $this->tempFilesDirectory)
       ->save();
+    $settings = [];
+    $settings['settings']['file_private_path'] = (object) [
+      'value' => $this->privateFilesDirectory,
+      'required' => TRUE,
+    ];
 
     // Manually configure the test mail collector implementation to prevent
     // tests from sending out emails and collect them in state instead.
diff --git a/core/tests/Drupal/KernelTests/KernelTestBase.php b/core/tests/Drupal/KernelTests/KernelTestBase.php
index fd7b864..8a73f82 100644
--- a/core/tests/Drupal/KernelTests/KernelTestBase.php
+++ b/core/tests/Drupal/KernelTests/KernelTestBase.php
@@ -1075,7 +1075,7 @@ public function __get($name) {
           return Settings::get('file_public_path', \Drupal::service('site.path') . '/files');
 
         case 'private_files_directory':
-          return $this->container->get('config.factory')->get('system.file')->get('path.private');
+          return Settings::get('file_private_path');
 
         case 'temp_files_directory':
           return file_directory_temp();