"None" is displayed. Files or directories are not shown.

This occurs if Enable file history option is not selected under the NDMP pane in the Job Properties as shown in the Figure below.

During the restore process, individual files can be selected for restore if file history was enabled for the backup job.
Backup Exec cannot gather sufficient file and directory information on an NDMP restore to accurately populate the Job Summary and Set Detail Information sections of the job history with the number of files, directories, files skipped, corrupt files, and files in use. These numbers always appear as 0.
Note:- NDMP backup sets cannot be cataloged unless the option to use storage media-based catalogs is selected as a catalog default.
Check the option for enabling file history and re-run the backup.