When you recover an undeleted file, you might find that its original name is no longer intact. This file renaming is a function of Windows rather than the undelete utility.
On a FAT partition, Windows strips the first character from the names of deleted files and directories that have 8.3 filenames. Windows leaves long filenames intact.
On an NTFS partition, all files that you delete directly from Windows or from the command prompt keep their full names, but files that you purge from the Recycle Bin receive new names. Windows renames each file with the format DDn.*. (The first D stands for "deleted," the second D is the drive letter representing the drive from which you deleted the files, and n is a sequential number. For example, Windows renames the first text file that it deletes from the D drive DD0.txt, renames the second text file DD1.txt, and so on.) Windows renames files that you send to the Recycle Bin in case you send another file with the same name to the Recycle Bin. Typically, the Recycle Bin keeps track of the original name and shields you from the new name. But when you empty the Recycle Bin, purged files lose their original names and are left with only the DDn.* name.