diff --git a/lib/server/minify.js b/lib/server/minify.js
index 7ef620a9..702cd6a6 100644
--- a/lib/server/minify.js
+++ b/lib/server/minify.js
@@ -40,8 +40,7 @@
                 
                 isChanged   = exec.with(IsChanged.isFileChanged, name),
                 isExist     = function(callback) {
-                    var func = exec.ret(callback, null);
-                    fs.exists(minifyName, func);
+                    fs.exists(minifyName, callback);
                 };
                 
                 exec.parallel([isChanged, isExist], function(error, changed, exists) {