diff --git a/atom/browser/api/atom_api_window.cc b/atom/browser/api/atom_api_window.cc
index 66ae006ce28b..455e2225a3a8 100644
--- a/atom/browser/api/atom_api_window.cc
+++ b/atom/browser/api/atom_api_window.cc
@@ -714,7 +714,7 @@ bool Window::SetThumbnailToolTip(const std::string& tooltip) {
 void Window::SetAppDetails(const mate::Dictionary& options) {
   base::string16 app_id;
   base::FilePath app_icon_path;
-  int app_icon_index;
+  int app_icon_index = 0;
   base::string16 relaunch_command;
   base::string16 relaunch_display_name;