diff --git a/modules/dgi_migrate_foxml_standard_mods/src/Plugin/migrate/process/FoxmlFile.php b/modules/dgi_migrate_foxml_standard_mods/src/Plugin/migrate/process/FoxmlFile.php
index 2bd412f..a3b16a6 100644
--- a/modules/dgi_migrate_foxml_standard_mods/src/Plugin/migrate/process/FoxmlFile.php
+++ b/modules/dgi_migrate_foxml_standard_mods/src/Plugin/migrate/process/FoxmlFile.php
@@ -94,7 +94,7 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
         $row,
         $destination_property,
       ),
-      'direct' => static::ensureNonWritable($value),
+      'direct' => $this->ensureNonWritable($value),
     };
   }
 
diff --git a/src/Plugin/migrate/process/EnsureNonWritableTrait.php b/src/Plugin/migrate/process/EnsureNonWritableTrait.php
index 28558cb..5b69409 100644
--- a/src/Plugin/migrate/process/EnsureNonWritableTrait.php
+++ b/src/Plugin/migrate/process/EnsureNonWritableTrait.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\dgi_migrate\Plugin\migrate\process;
 
+use Drupal\Core\File\FileSystemInterface;
 use Drupal\migrate\MigrateSkipRowException;
 
 /**
@@ -27,30 +28,28 @@ trait EnsureNonWritableTrait {
    * @throws \Drupal\migrate\MigrateSkipRowException
    *   If the file appears to be writable/deletable.
    */
-  protected static function ensureNonWritable(string $path) : string {
-    $file = new \SplFileInfo($path);
-
-    if (!$file->isFile()) {
+  protected function ensureNonWritable(string $path) : string {
+    if (!is_file($path)) {
       throw new MigrateSkipRowException(strtr('Source ({path}) does not appear to be a plain file; skipping row.', [
         '{path}' => $path,
       ]));
     }
-    if ($file->isDir()) {
+    if (is_dir($path)) {
       throw new MigrateSkipRowException(strtr('Source ({path}) appears to be a directory; skipping row.', [
         '{path}' => $path,
       ]));
     }
-    if (!$file->isReadable()) {
+    if (!is_readable($path)) {
       throw new MigrateSkipRowException(strtr('Source ({path}) does not appear to be readable; skipping row.', [
         '{path}' => $path,
       ]));
     }
-    if ($file->isWritable()) {
+    if (is_writable($path)) {
       throw new MigrateSkipRowException(strtr('Source ({path}) appears to be writable(/deletable); skipping row.', [
         '{path}' => $path,
       ]));
     }
-    if ($file->getPathInfo()?->isWritable()) {
+    if (is_writable($this->getFileSystem()->dirname($path))) {
       throw new MigrateSkipRowException(strtr('Directory of source ({path}) appears writable(/deletable); skipping row.', [
         '{path}' => $path,
       ]));
@@ -59,4 +58,25 @@ protected static function ensureNonWritable(string $path) : string {
     return $path;
   }
 
+  /**
+   * Drupal's file system service.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected FileSystemInterface $fileSystem;
+
+  /**
+   * Accessor for Drupal's file system service.
+   *
+   * @return \Drupal\Core\File\FileSystemInterface
+   *   Drupal's file system service.
+   */
+  protected function getFileSystem() : FileSystemInterface {
+    if (!isset($this->fileSystem)) {
+      $this->fileSystem = \Drupal::service('file_system');
+    }
+
+    return $this->fileSystem;
+  }
+
 }
diff --git a/src/Plugin/migrate/process/NonWritable.php b/src/Plugin/migrate/process/NonWritable.php
index 5825f8d..d1fc3e9 100644
--- a/src/Plugin/migrate/process/NonWritable.php
+++ b/src/Plugin/migrate/process/NonWritable.php
@@ -26,7 +26,7 @@ class NonWritable extends ProcessPluginBase {
    * {@inheritDoc}
    */
   public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
-    return static::ensureNonWritable($value);
+    return $this->ensureNonWritable($value);
   }
 
 }