BrightStore ARCserve Backup r11 or 11.1 Backup issue

Hi all,

I m facing problem in BrightStore ARCserve Backup r11 or 11.1 in that i want the Server Backup need to be done in USB HDD as it is not happening properly. It is showing us that Backup Completed Successfully, But when are trying to restore the files in any folder the files are not showing in that folder.
So please give me the solutions for taking backup on regular basis.