I have an external hard drive and I plan to put iPhone backups on it.

I did symlink to it this way:

ln -s /Volumes/external/Backup ~/Library/Application Support/MobileSync

When I'm trying to do a backup of my iPhone normally from iTunes, I get an error:

However my drive has 1 TB of free space. What's wrong?

2 Answers 2


iTunes doesn't know you've symlinked the MobileSync folder, so still checks the normal disk for its free space. Make sure there's enough free space on the disk containing your home folder, even though that space won't be consumed because of the symlink.

  • Well, df -h shows that i have 90 gb's of free space on my normal disk. Isn't that enough? Nov 15, 2016 at 2:42
  • How big is the phone? Also, what model (5, 6, etc) is it?
    – Kisa Ayano
    Nov 22, 2016 at 3:48
  • I have a 256 GB iPhone so it's pretty impossible to have enough space on the Mac. Maybe there's a way to temporary fake available space on the Mac?
    – AnthoPak
    Dec 10, 2022 at 14:28

I could just check today that iTunes is not that stupid, it checks the free space on the symlinked folder. In my case there was a formatting problem that made macOS believe that the symlinked volume was much smaller than its real capacity. Some wrangling with disk utility cured the problem. Maybe that's what was happening in your case.

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