diff -u b/core/modules/file/file.module b/core/modules/file/file.module
--- b/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -970,14 +970,14 @@
 
     default:
       // Unknown error
-      $error_to_log = 'The file ' . $file_info->getFilename() . ' could not be saved. An unknown error has occurred.';
+      $error_to_log = 'The file ' . $original_file_name . ' could not be saved. An unknown error has occurred.';
       break;
   }
   if (isset($error_to_log)) {
     // Unconditionally display an error message to the end user. This is a
     // generic message since the errors that trigger this represent server-level
-    // problems that end users should not know about (and cannot fix by
-    // attempting the upload again).
+    // problems that end users should not know about and cannot fix by
+    // attempting the upload again.
     \Drupal::messenger()->addError(t('The file %file could not be saved. An unknown error has occurred.', ['%file' => $original_file_name]));
     \Drupal::logger('file')->error($error_to_log);
     return FALSE;
diff -u b/core/modules/file/tests/src/Kernel/FileModuleTest.php b/core/modules/file/tests/src/Kernel/FileModuleTest.php
--- b/core/modules/file/tests/src/Kernel/FileModuleTest.php
+++ b/core/modules/file/tests/src/Kernel/FileModuleTest.php
@@ -36,7 +36,7 @@
     $this->assertFalse(\_file_save_upload_single($file_info, 'name'));
 
     // Check the displayed user message.
-    $expected_message = new TranslatableMarkup("The file %file could not be saved. An unknown error has occurred.", ['%file' => $file_name]);
+    $expected_message = new TranslatableMarkup('The file %file could not be saved. An unknown error has occurred.', ['%file' => $file_name]);
     $this->assertEquals($expected_message, \Drupal::messenger()->all()['error'][0]);
 
     // Check the logged message.