TV recording settings default behavior is saved in the registry, but for each individual recording subscription, the info (such as the clean up mode info) is saved in the TV recoding rules.
Yaobing, do the recording rules use the "Date Recorded" field plus the number of days to keep a recording to work out whether to delete a file?
Because the "Date Recorded" is an editable field. If using a rule that says "Delete after X days", then wouldn't setting the "Date Recorded" well into the future mean that it was "never" deleted?
Of course there are still the "Date Imported", which the default views are sorted by, and "Date Modified" fields available, so it is easy to tell when the video file was created.
Just a thought, and possible work around.