diff --git a/includes/file.inc b/includes/file.inc
index e9a567e..742e4d2 100644
--- a/includes/file.inc
+++ b/includes/file.inc
@@ -443,7 +443,7 @@ function file_prepare_directory(&$directory, $options = FILE_MODIFY_PERMISSIONS)
     return FALSE;
   }
   // The directory exists, so check to see if it is writable.
-  $writable = is_writable($directory);
+  $writable = is_writable(drupal_realpath($directory) == FALSE ? $directory : drupal_realpath($directory));
   if (!$writable && ($options & FILE_MODIFY_PERMISSIONS)) {
     return drupal_chmod($directory);
   }