I have nothing excluded in Time Machine Preferences. My backup external drive failed about a year ago: I replaced it and backups continued. Had to restore an application recently: found the applications folder in Time Machine was empty, however far back I went. Does Time Machine know that I replaced the backup drive? If not, perhaps /applications has not been backed up since nothing has changed since I replaced the drive - ? But I have been told that the backup information is stored on the backup drive, so Time Machine should know that the drive was replaced and do a full backup as the first one - ? If that is the problem, how do I force Time Machine to do a full backup?