There are four main ways to save data (or 'backup') to your external drive: manually (using the copy & paste or the drag & drop method), creating image/clone backups, using a backup software, and using backup programs included within Windows or MacOS.
To copy the data to the external hard drive: Please see the ' File system compatibility between operating systems' section below. Also, please note there may be a file system compatibility issue. Applications will not function when they are copied to a different system. pictures, documents, music, etc.) and not applications. It is recommended that you only copy data (i.e. In most cases you can use your external hard drive to copy data from one computer to another. Tips and troubleshooting tricks for moving data between computers when your external drive is formatted for use within MacOS.
