Close #4155
diff --git a/system/helpers/file_helper.php b/system/helpers/file_helper.php
index cd1c641..f6cb162 100644
--- a/system/helpers/file_helper.php
+++ b/system/helpers/file_helper.php
@@ -343,7 +343,7 @@
 
 		if ( ! is_array($mimes))
 		{
-			$mimes =& get_mimes();
+			$mimes = get_mimes();
 
 			if (empty($mimes))
 			{