For example
NSString *path = @"XXX";
id obj = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
and somewhere else is going to delete this file by removeItemAtPath, whether it is safe to do that? as I know, if I write an object to the file with archiver and I modify that object meanwhile, it will cause crash, but I don't understand the essence of the that, so I wonder what will happen if I operate like this.