diff --git a/atom/common/api/atom_api_shell.cc b/atom/common/api/atom_api_shell.cc
index 0e8d89584e6df..2dbfbc6537cc2 100644
--- a/atom/common/api/atom_api_shell.cc
+++ b/atom/common/api/atom_api_shell.cc
@@ -80,8 +80,9 @@ v8::Local<v8::Promise> OpenExternal(
 #endif
     mate::Arguments* args) {
 
-  v8::Locker locker(args->isolate());
+  mate::Locker locker(args->isolate());
   v8::HandleScope handle_scope(args->isolate());
+
   scoped_refptr<atom::util::Promise> promise =
       new atom::util::Promise(args->isolate());