diff --git a/app/lib/zap/controller.js b/app/lib/zap/controller.js
index f2f755b2..a7198f51 100644
--- a/app/lib/zap/controller.js
+++ b/app/lib/zap/controller.js
@@ -112,6 +112,12 @@ class ZapController {
         this.mainWindow.hide()
       }
     })
+
+    // Dereference the window object, usually you would store windows in an array if your app supports multi windows,
+    // this is the time when you should delete the corresponding element.
+    this.mainWindow.on('closed', () => {
+      this.mainWindow = null
+    })
   }
 
   // ------------------------------------
diff --git a/app/main.dev.js b/app/main.dev.js
index 69955f79..1dcbd737 100644
--- a/app/main.dev.js
+++ b/app/main.dev.js
@@ -109,7 +109,9 @@ app.on('ready', () => {
       event.preventDefault()
       zap.terminate()
     } else {
-      zap.mainWindow.forceClose = true
+      if (zap.mainWindow) {
+        zap.mainWindow.forceClose = true
+      }
     }
   })