I'm having a problem with the internal SSD on one of my Macs running 10.10. It was working fine when I was browsing the web one day and then suddenly froze with the spinning beachball; I couldn't force quit (it was truly hung) so I forced a restart and now the computer won't boot at all. I've tried the following with no success:

  1. Booting into the recovery partition and repairing the disk with Disk Utility.
  2. Booting on an external USB 10.10 installer and repairing the disk with Disk Utility.
  3. Booting in target disk mode and repairing the disk with Disk Utility.
  4. Booting in target disk mode and trying everything I can think of with diskutil in Terminal.

At this point I've given up on Disk Utility and have been looking for the right combination of diskutil, fsck, and gpt to get things working. I have some data that will be lost so reformatting is not an option.

Here is some of the relevant info:

$ diskutil list:

/dev/disk1 (external):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         251.0 GB   disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:          Apple_CoreStorage Macintosh HD            250.1 GB   disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

$ diskutil info disk1:

   Device Identifier:        disk1
   Device Node:              /dev/disk1
   Whole:                    Yes
   Part of Whole:            disk1
   Device / Media Name:      APPLE SSD SD256E

   Volume Name:              Not applicable (no file system)

   Mounted:                  Not applicable (no file system)

   File System:              None

   Content (IOContent):      GUID_partition_scheme
   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 Thunderbolt
   SMART Status:             Verified

   Total Size:               251.0 GB (251000193024 Bytes) (exactly 490234752 512-Byte-Units)
   Volume Free Space:        Not applicable (no file system)
   Device Block Size:        512 Bytes

   Read-Only Media:          Yes
   Read-Only Volume:         Not applicable (no file system)

   Device Location:          External
   Removable Media:          No

   OS 9 Drivers:             No
   Low Level Format:         Not supported

$ diskutil verifyDisk disk1:

Started partition map verification on disk1
Checking prerequisites
Checking the partition list
Checking the partition map size
Checking for an EFI system partition
Checking the EFI system partition's size
Checking the EFI system partition's file system
Problems were found with the partition map which might prevent booting
Error: -69766: The partition map needs to be repaired because there's a problem with the EFI system partition's file system
Underlying error: 8: POSIX reports: Exec format error

$ sudo diskutil repairDisk disk1:

Unable to repair this whole disk: A writable disk is required (-69772)

$ sudo gpt -r show /dev/disk1:

      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640  488555536      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
  488965176    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  490234712          7         
  490234719         32         Sec GPT table
  490234751          1         Sec GPT header

$ diskutil cs list:

CoreStorage logical volume groups (1 found)
+-- Logical Volume Group xxxxxxxx-xxxx-xxxx-xxxx-22CC7A9CEE24
    Name:         Macintosh HD
    Status:       Offline
    Size:         250140434432 B (250.1 GB)
    Free Space:   249788108800 B (249.8 GB)
    +-< Physical Volume xxxxxxxx-xxxx-xxxx-xxxx-907CB441E882
        Index:    0
        Disk:     disk1s2
        Status:   Online
        Size:     250140434432 B (250.1 GB)
  • @klanomath I added the additional information. I suspect there could be an issue with the Core Storage/encrypted partition since I can't see any logical volumes but I was trying to start with the EFI partition. I really only care about the data in the CS logical volume, though.
    – sbooth
    Dec 27, 2015 at 14:24
  • Only a partial backup unfortunately
    – sbooth
    Dec 27, 2015 at 15:12
  • I'm willing to try anything. If you have any guidance it would be much appreciated! I have seen guides to deleting and recreating the EFI partition and also copying an existing one using dd but I didn't want to do anything potentially destructive.
    – sbooth
    Dec 27, 2015 at 15:29
  • Do you have a spare USB flash drive/thumb drive and a yosemite installer?
    – klanomath
    Dec 27, 2015 at 16:56
  • Yes, I made a 10.10 USB bootable installer on a flash drive. I used it to try and help but didn't get very far.
    – sbooth
    Dec 27, 2015 at 17:09

4 Answers 4


I had a similar issue with a MacBook pPo A 1278. HDD as internal device does not boot.

Connected as external USB drive -> HDD boot. Problem solved by replacing the internal SATA cable for (currently) $16.

See ifixit com (only) for the replacement instructions of the SATA cable.


The EFI can be recovered easily. The real issue is the missing Logical Volume Family and the Logical Volume in the CoreStorage Logical Volume Group. The LVF is the container for the actual encrypted Logical Volume.

There is no known tool to restore a deleted LVF/LV. Simply adding a LV with diskutil cs createVolume lvgUUID filesystem size will overwrite parts of the previous LV.

There is small chance to manually manipulate the superior LVG container and recover the FileVault volume. This is subject of further research/investigation.

Recover the EFI:

Create a new EFI on an external disk and dd the result to the broken EFI. It might be sufficient to just use an arbitrary EFI of another system disk – I don't know it!

  • Create a Yosemite bootable thumb drive installer
  • Attach the thumb drive and a spare external hard drive (16 GB) or an empty second thumb drive (at least 16 GB) to the "broken" Mac.
  • Install Yosemite to the external drive/thumb drive
  • Configure Yosemite
  • Enable FileVault (use the same passwords/passphrase as previously on the broken system) and if asked reboot.
  • Backup the current EFI of the SSD:

    dd if=/dev/disk0s1 of=~/Desktop/EFISSD.raw bs=1m
  • Reboot to one of the Recovery HDs by pressing cmdR
  • Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter: diskutil list to get the disk identifiers.
  • Now use dd to replace the broken EFI by the new EFI (assuming that the external disk has the disk identifier disk2 – check the sizes of the various disk to determine the correct one):

    dd if=/dev/disk2s1 of=/dev/disk0s1 bs=1m

Work in progress - This is subject of further research/investigation

Recover a deleted/vanished FileVault Logical Volume Family/Logical Volume

One possibility may be the following procedure:

  • Boot to an external system
  • dd the relevant parts of the SSD (the encrypted part is easily detectable) to a file on a separate disk:

    dd if=/dev/disk0 of=/Volumes/ExternalDisk/encrypted.raw skip=x count=y bs=512

    with x: the number of the first blocks on the disk which are not encrypted (~420000) and y: number of encrypted blocks

  • dd the Recovery HD partition to a RecoverHD.raw file because it contains at least one important key.
  • Reinstall OS X on the SSD with the same usernames and passwords as previously
  • enabling FileVault
  • Boot to an external disk
  • dd the file back and replacing the actual content of the Logical Volume Family/Logical Volume:

    dd if=/Volumes/ExternalDisk/encrypted.raw of=/dev/disk0 seek=z bs=512b

    with z: the number of the first blocks on the disk which are not encrypted

  • dd the RecoveryHD.raw file back and replacing the actual content of the new Recovery HD.

This might fail due to varying keys, different salts (if salts are used at all) or other reasons.

  • I tried the first part of this answer (recovering the ESP) and sadly nothing changed. I was able to copy a working EFI partition from a thumb drive to the broken SSD but verifyDisk still shows that the partition map needs repairs and repairDisk says it can't create the EFI partition.
    – sbooth
    Jan 2, 2016 at 2:54

Having a similar issue. Mac hard drive stopped working while inside, but when you connect via USB it works perfectly fine. Even got new hard drive, but still got an issue with booting from hd inside mac. Machine can see the disk. I’ve installed OS X on new hard drive via USB connection, but when I put hd inside it won’t boot. Crazy world, no idea what's wrong with it. But in terms of data, try connecting it via USB and you may find that your data is safe.

  • Have you found a solution since then? I have the same problem. Bought new ssd, reinstalled osx and I still get the circle crossed with line on boot. If I verify disk on recovery mode I get "The partition map needs to be repaired..." New disk, new OS, makes no sense at all.
    – DimiDak
    Apr 19, 2021 at 20:54

To be real frank it seems to me that the problem is more likely to be on the media (SSD) than on the software.

If the data is important, I suggest you look into professional data recovery services ASAP as the problem might worsen in case of a hardware failure. (Yes, I witnessed a Mac with SSD going from still-kind-of-bootable to the-disk-completely-not-detected between several consecutive boots when I worked at one of the service centre)

Core Storage volumes are usually quite durable but almost never recoverable with included tools in case they finally breaks (especially when it's encrypted). I don't think any combination of fsck / gpt / diskutil would work… but good luck.

  • Thanks for the answer. What data recovery services do you know of that are familiar with Core Storage?
    – sbooth
    Dec 27, 2015 at 18:15

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