NSDictionary error on real device

Question

Following code work fine on emulator, but on real device i got exception:

if ([[NSUserDefaults standardUserDefaults] objectForKey:@"favorites"] == nil)
{
    NSMutableDictionary *favorites = [[NSMutableDictionary alloc] init];
    [[NSUserDefaults standardUserDefaults] setObject:favorites forKey:@"favorites"];
}

Exception on next line of code:

NSMutableDictionary *favorites = [NSMutableDictionary dictionaryWithDictionary:
    [[NSUserDefaults standardUserDefaults] objectForKey:@"favorites"]];

Here debugger message:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason:
'*** -[NSDictionary initWithDictionary:copyItems:]: dictionary argument is not
an NSDictionary'

I use iPad device with iOS 7.1.

EDIT

On real devise the old version of the application used this key in NSUserDefaults for NSArray. Thanks for help!

Answer 1

It looks like what is already stored in your user preferences is not a dictionary.

You could change the test at the beginning like this:

if (! [[[NSUserDefaults standardUserDefaults] objectForKey:@"favourites"] 
           isKindOfClass:[NSDictionary class]])

This will cover the case that there is nothing in your user defaults, or that you have an object there that isn't a dictionary.