The extension .GHO refers to files of the type, Norton Ghost Backup files. These are the backup files created by Norton backup utility to create exact same image files of the hard disk as back up resources.

The file structure is designed in such a way that it copies all the data on the disk and also creates a separate metadata table entry for the same to create an exact replica of a hard disk. This image file can then be transported to some other storage for backup. Once the cleaning or formatting operation takes place, the ghost file can again be used to restore the state of the hard disk back to its original form.