iTunes would let you save the necessary data on iPhone and you should know what iTunes backup includes. The advantage of iTunes is that you could save your iPhone by one click, but you would find it could also be a disadvantage because you could not save only what you want. To find iTunes backup on Mac, you could use Spotlight or iTunes itself, but you still could not view what’s in it without a tool. You need the help of iPhone backup browser.
To backup iPhone to external hard drive with iTunes, you need to create a destination in external hard drive and use symlink to tell iTunes to save iPhone backup to external hard drive. Follow the steps:
Step 1. Connect iPhone and external hard drive to Mac. Create a folder named MobileSync in external hard drive.
Step 2. Find your old iPhone backup on Mac. You could open iTunes > click iTunes > select Preferences > select Devices > select a backup > click Show in Finder.
Step 3. Move the whole folder, Backup, to the folder MobileSync in external hard drive. If you don’t need these old backups, you could delete them and then create a folder named Backup in external hard drive.
Step 4. Open Terminal on Mac. Enter ln-s/Volumes/External/Backup~/Library/Application\Support/MobileSync/Backup. You should know that “External” should be the name of your external hard drive.
Step 5. Select your iPhone in the sidebar of iTunes. Click Back Up Now. After the process has been finished, you could check whether your iPhone backup has been saved to external hard drive.
If you use Mac OS Catalina, you could not find iTunes on Mac, because it has been divided into 3 parts, Podcasts, TV and, Music. You could directly backup your iPhone to external hard drive with Finder.
Thanks
[Link Edited by Moderator]
