title: NSUserDefaults standardUserDefaults stopped working using iOS 9.3.1
body: <p>I'm using this code in my app:</p>
  
  <pre><code>if ([[NSUserDefaults standardUserDefaults] objectForKey:@"First_RUN"] == NULL) {
      [self tutorial:nil];
      [[NSUserDefaults standardUserDefaults] setInteger:1 forKey:@"First_RUN"];
      [[NSUserDefaults standardUserDefaults] synchronize];
  }
  </code></pre>
  
  <p>I'm using this code to know when the first time the app runs, if that is the case I show a tutorial.
  After upgrading to 9.3.1 I found out that it stopped working so that every time the app runs tutorial appears.
  Tried to debug this but it seems that [NSUserDefaults standardUserDefaults] just stopped working.</p>
  
  <p>I'm using old Xcode for this app (6.4). Any help using [NSUserDefaults standardUserDefaults] in another way or explanation for this issue would help (I have this kind of code in many of my apps and it all breaks now).</p>
  
  <p>Just to make things clear. This code runs perfectly with iOS 9.3 but not with iOS 9.3.1, I guess that something is broken or changed. </p>
  
  <p>UPDATE: I created a test project for that (to isolate the issue), and it seems that simulator is fine but running on device with 9.3.1 even using Xcode 7.3 makes same issue: <a href="https://sidan5@bitbucket.org/sidan5/nsuserdefaultsdemo.git" rel="nofollow">https://sidan5@bitbucket.org/sidan5/nsuserdefaultsdemo.git</a></p>