diff --git a/atom/browser/api/atom_api_system_preferences_mac.mm b/atom/browser/api/atom_api_system_preferences_mac.mm
index 64732c3725..b078db585d 100644
--- a/atom/browser/api/atom_api_system_preferences_mac.mm
+++ b/atom/browser/api/atom_api_system_preferences_mac.mm
@@ -152,6 +152,13 @@ void SystemPreferences::RegisterDefaults(mate::Arguments* args) {
   } else {
     @try {
       NSDictionary* dict = DictionaryValueToNSDictionary(value);
+      // for (id key in dict) {
+      //   id value = [dict objectForKey:key];
+      //   if (value == nil) {
+      //     printf("HELLO\n");
+      //     args->ThrowError("Invalid userDefault data provided");
+      //   }
+      // }
       [[NSUserDefaults standardUserDefaults] registerDefaults:dict];
     } @catch (NSException* exception) {
       args->ThrowError("Invalid userDefault data provided");
diff --git a/spec/api-system-preferences-spec.js b/spec/api-system-preferences-spec.js
index 27955b3d70..36902ffaf1 100644
--- a/spec/api-system-preferences-spec.js
+++ b/spec/api-system-preferences-spec.js
@@ -2,7 +2,7 @@ const assert = require('assert')
 const {remote} = require('electron')
 const {systemPreferences} = remote
 
-describe.only('systemPreferences module', () => {
+describe('systemPreferences module', () => {
   describe('systemPreferences.getAccentColor', () => {
     before(function () {
       if (process.platform !== 'win32') {
@@ -66,7 +66,6 @@ describe.only('systemPreferences module', () => {
         1,
         null,
         new Date(),
-        { 'one': null }
       ]
 
       for (const badDefault of badDefaults) {