How can i get itunes to backup my iphone with limited disk. I linked the backup dir to an ext drive with space yet still won't backup? On OSX yosemite, a machine with limited disk space free.

In order to backup my iphone, I've linked the  ~/Library/Application Support/MobileSync/Backup dir to an external drive.

iTunes, correctly displays the existing backups in that dir.

But iTunes backup, fails with an insufficient disk space free.

Is it failing to check the free space on the volume that the Backup folder is on?

The boot volume certainly does not have enough free space.

How can I work around this, without deleting data?


osx: 10.10.3 (14D136)
iTunes: 12.1.2.27


update: have tried on another machine (with sufficient space) still received the same error.

Suspecting bugs, or permissions issues.
Perhaps it is better to move something else to the external disk, like the music or movies library. These are normally very large and thus this gives you ample space on the startup disk.