把数组存进 Core Data 遇到的问题

[DavidHu]

[MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext) {
Course *course = [Course MR_createInContext:localContext];

course.classesName = classesName;
                course.teacherName = teacherName;
                course.classroom = @"体育馆";
                course.startTime = startTime;
                course.weekday = weekday;
                course.weekNumber = [NSKeyedArchiver archivedDataWithRootObject:allweekNumber];
                course.howLong = howLong;

            } completion:^(BOOL success, NSError *error) {
                NSLog(@"SUCCESS: %d, with ERROR: %@", success, error);
            }];

这里是代码，里面NSKeyedArchiver那行感觉有问题，因为数据肯定都对，但是存的时候有时候存不上会在这句崩溃，有的时候是能存上，但是读不出来。求教各位

[DavidHu]

会报一个EXC_BAD_ACCESS(code:1 ....的错