Doing code analysis of the project and get the message "Reference-counted object is used after it is released" on the line [defaults setObject: deviceUuid forKey: @ "deviceUuid"]; I watched this topic Obj-C, Reference-counted object is used after it is released? But the solution is not found. ARC disabled. // Get the users Device Model, Display Name, Unique ID, Token & Version Number UIDevice *dev = [UIDevice currentDevice]; NSString *deviceUuid; if ([dev respondsToSelector:@selector(uniqueIdentifier)]) deviceUuid = dev.uniqueIdentifier; else { NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; id uuid = [defaults objectForKey:@"deviceUuid"]; if (uuid) deviceUuid = (NSString *)uuid; else { CFStringRef cfUuid = CFUUIDCreateString(NULL, CFUUIDCreate(NULL)); deviceUuid = (NSString *)cfUuid; CFRelease(cfUuid); [defaults setObject:deviceUuid forKey:@"deviceUuid"]; } } Please help find the cause.