Portable hard drives are not a permanent aspect of the computer’s hardware configuration, they are subject to many of the same hardware technologies and procedures. One of the most notable is that of a portable hard drive’s ability to be backed up on any computer to which it is connected. The native tools within the Windows operating system allow for portable hard drives to be backed up on the primary system’s drive, a reversal of the standard hard drive backup.
Right-click the icon for the portable hard drive that appears in Windows Explorer.
Click the "Set up backup" link beneath the "Backup" heading.
Click the "Next" and then "Save settings and run backup" buttons.