If you use a lot this comportment it's indicated to your own NSMutableArray class (subclass of NSMutableArray) which doesn't increase the retain count.
You should have something like this:
-(void)addObject:(NSObject *)object { [self.collection addObject:[NSValue valueWithNonretainedObject:object]];}-(NSObject*) getObject:(NSUInteger)index { NSValue *value = [self.collection objectAtIndex:index]; if (value.nonretainedObjectValue != nil) { return value.nonretainedObjectValue; } //it's nice to clean the array if the referenced object was deallocated [self.collection removeObjectAtIndex:index]; return nil;}