diff --git a/core/modules/migrate_drupal_ui/src/Batch/MigrateUpgradeImportBatch.php b/core/modules/migrate_drupal_ui/src/Batch/MigrateUpgradeImportBatch.php
index c9c19a5..135e011 100644
--- a/core/modules/migrate_drupal_ui/src/Batch/MigrateUpgradeImportBatch.php
+++ b/core/modules/migrate_drupal_ui/src/Batch/MigrateUpgradeImportBatch.php
@@ -111,13 +111,18 @@ public static function run($initial_ids, $config, &$context) {
     $definition = \Drupal::service('plugin.manager.migration')->getDefinition($migration_id);
     $configuration = [];
 
-    // @todo Find a way to avoid this in https://www.drupal.org/node/2804611.
+    // Set the source plugin constant, source_base_path, for all migrations with
+    // a file entity destination.
+    // @todo https://www.drupal.org/node/2804611.
+    //   Find a way to avoid having to set configuration here.
     if ($definition['destination']['plugin'] === 'entity:file') {
-      // Make sure we have a single trailing slash.
-      if ($definition['source']['plugin'] === 'd7_file_private') {
-        $configuration['source']['constants']['source_base_path'] = rtrim($config['source_private_file_path'], '/') . '/';
-      }
-      $configuration['source']['constants']['source_base_path'] = rtrim($config['source_base_path'], '/') . '/';
+      // Use the private file path if the scheme property is set in the source
+      // plugin definition and is 'private' otherwise use the public file path.
+      $scheme = $definition['source']['scheme'] ?? NULL;
+      $base_path = ($scheme === 'private' && $config['source_private_file_path'])
+        ? $config['source_private_file_path']
+        : $config['source_base_path'];
+      $configuration['source']['constants']['source_base_path'] = rtrim($base_path, '/') . '/';
     }
 
     /** @var \Drupal\migrate\Plugin\Migration $migration */
diff --git a/core/modules/migrate_drupal_ui/src/Form/CredentialForm.php b/core/modules/migrate_drupal_ui/src/Form/CredentialForm.php
index 54b431f..ea7f6c9 100644
--- a/core/modules/migrate_drupal_ui/src/Form/CredentialForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/CredentialForm.php
@@ -193,7 +193,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#type' => 'textfield',
       '#title' => $this->t('Document root for private files'),
       '#default_value' => '',
-      '#description' => $this->t('To import private files from your current Drupal site, enter a local file directory containing your site (e.g. /var/www/docroot).'),
+      '#description' => $this->t('To import private files from your current Drupal site, enter a local file directory containing your site (e.g. /var/www/docroot). Leave blank to use the same value as Public files directory.'),
       '#states' => [
         'visible' => [
           ':input[name="version"]' => ['value' => '7'],
diff --git a/core/modules/migrate_drupal_ui/src/Form/ReviewForm.php b/core/modules/migrate_drupal_ui/src/Form/ReviewForm.php
index 0474c47..081992f 100644
--- a/core/modules/migrate_drupal_ui/src/Form/ReviewForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/ReviewForm.php
@@ -240,6 +240,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $config['source_base_path'] = $this->store->get('source_base_path');
+    $config['source_private_file_path'] = $this->store->get('source_private_file_path');
     $batch = [
       'title' => $this->t('Running upgrade'),
       'progress_message' => '',
diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
index d64b001..2296a6b 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
@@ -310,4 +310,33 @@ public function assertUserLogIn($uid, $pass) {
     $this->drupalLogin($user);
   }
 
+  /**
+   * Provides the source base path for private files for the credential form.
+   *
+   * @return string|null
+   *   The source base path.
+   */
+  protected function getSourcePrivateBasePath() {
+    return NULL;
+  }
+
+  /**
+   * Checks public and private files are copied but not temporary files.
+   */
+  protected function assertFileMigrations() {
+    $fs = \Drupal::service('file_system');
+    $files = $this->getManagedFiles();
+    foreach ($files as $file) {
+      preg_match('/^(private|public|temporary):/', $file['uri'], $matches);
+      $scheme = $matches[1];
+      $filepath = $fs->realpath($file['uri']);
+      if ($scheme === 'temporary') {
+        $this->assertFileNotExists($filepath);
+      }
+      else {
+        $this->assertFileExists($filepath);
+      }
+    }
+  }
+
 }