UndeleteOnClick provides an estimation of the chances of recovering all or part of the deleted file:
Good: There is a good chance the file can be undeleted completely.
Fair: Some parts of the deleted file conflict with parts of other deleted files.
Poor: Some parts of the deleted file conflict with existing files.
Lost: All parts of the deleted file are being used again by existing files, i. e. it has been completely overwritten.
Unknown: Damage estimation failed or was not performed at all.