I am not able at the moment to find a definitive explanation of how Time Machine works, but it was my understanding that it is a backup utility, not an archiving utility. At some later time, the only copy in the Time Machine backups of the file that was deleted from the source volume after being backed up by Time Machine will exist only in what will have become a very old Time Machine backup. If that backup is deleted to create more free space, the file will be nowhere.
If a file still exists on the source volume, then it should be present in at least one of the Time Machine backups, but if it has been deleted from the source volume, it may not be in the Time Machine, depending on elapsed time and disk space use.
Please correct me if I have misunderstood how Time Machine works. Also, I do not understand why this text is frequently quoted but seems to have no original source on the Web:
(from http://en.wikipedia.org/wiki/Time_Machine_%28Mac_OS%29)
"Time Machine is a backup utility, not an archival utility, it is not intended as offline storage. Time Machine captures the most recent state of your data on your disk. As snapshots age, they are prioritized progressively lower compared to your more recent ones."[citation needed]
