Index: units/helpers/minifiers/minify_helper.php
===================================================================
--- units/helpers/minifiers/minify_helper.php	(revision 14094)
+++ units/helpers/minifiers/minify_helper.php	(working copy)
@@ -209,7 +209,7 @@
 
 			unlink($tmp_file);
 
-			if (!is_null($compressed_string)) {
+			if (!is_null($compressed_string) && $compressed_string) {
 				$string = $compressed_string;
 				return ;
 			}