Back up iphone to an external drive
I dont have enough storage on my mac to back up my iphone can I choose an external drive instead?
Basically, no. Apple says the following about iPhone backups to a Mac:
- The Finder and iTunes save backups to a Backup folder. The location of the Backup folder varies by operating system. Though you can copy the Backup folder, you should never move it to a different folder, external drive, or network drive.
That would indicate that you can move or delete backup to make space, but you cannot change the default location where the backups will go to on the Mac.
Ref: Locate backups of your iPhone, iPad, and iPod touch - Apple Support