Unfortunately my 2012 MacBook Air came off second best with a cup of coffee. Everything toasted except the SSD! As luck would have it, I have access to a 2011 MacBook Air (El Capitan) which I am now using. The only issue is I would like to get the data off the old one.

I have removed the SSD, purchased a SATA converter which I plug the SSD into, and then a SATA -> USB cable to plug this into the 2011 MacBook Air.

When I plug this in, the disk does not mount. From inside the OS I can

  1. See the SSD in Disk Utility however it won't let me mount (button disabled)
  2. Run First Aid, which runs successfully with no issues

From single-user mode, I have tried the following

  • fsck /dev/disk2s2 - this says 'unknown volume signature : 0' and then gives a series of hex readouts
  • sudo fdisk /dev/disk2s2 - this results in 4 rows, all of which have zeroes in every column entry
  • 4
    First guess, it's formatted as APFS, which El Capitan cannot read. You'll need a machine running Sierra or newer.
    – Tetsujin
    Commented Jul 1, 2019 at 7:02
  • @Tetsujin That sounds like it could make a great answer!
    – grg
    Commented Jul 1, 2019 at 22:19
  • Thank you both - that was spot-on! Was able to read it immediately once I upgraded to High Sierra. I then could not access the folders (permission issues) however got around this by right-clicking 'get info', clicking the padlock and authenticating myself, then adding myself as a user to each relevant folder. Thank you so much for your help! Commented Jul 2, 2019 at 6:22

1 Answer 1


Added as an answer after comments...

Initially a guess, that the disk was formatted APFS, which would be unreadable by El Capitan.

Upgrading to High Sierra would enable the disk to be read & written as normal.

As regards permissions; you could either add yourself to the user list, as an ACL, or you could just Get Info on the drive itself & check the 'Ignore ownership on this volume' box.

enter image description here

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .