How to repair HFS+ partition?

Question

So somehow my 2013 Retina MacBook Pro's internal SSD went and got its partition map messed up. I was using it, put it to sleep, and when I woke it back up about an hour later I was presented with a black screen. Forced a shutdown and on reboot it gives me a blank black screen and that's it.

The hard drive shows up when I hold down option on boot, but obviously does not work.

Disk Utility shows the disk as 251 GB unformatted with a child count of 3. Running diskutil list shows me the children, and they look correctish.

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Macintosh HD            250.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

output of gpt -r show /dev/disk0:

    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

output of diskutil cs list

CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 97EFE039-8BB4-4907-8739-2D9636F68947
=========================================================
Name:         Macintosh HD
Status:       Offline
Size:         250140434432 B (250.1 GB)
Free Space:   249804886016 B (249.8 GB)
|
+-< Physical Volume 13CEA9C7-10ED-438D-A4C0-6F4C18FC0335
    ----------------------------------------------------
    Index:    0
    Disk:     disk0s2
    Status:   Online
    Size:     250140434432 B (250.1 GB)

fsck output:

   Executing fsck_cs (version 517.20.1)
** Checking volume
** disk0s2: Scan for Volume Headers
** disk0s2: Scan for Disk Labels
** Logical Volume Group 97EFE039-8BB4-4907-8739-2D9636F68947 on 1 device
** disk0s2: Scan for Metadata Volume
** Logical Volume Group has a 16 MB Metadata Volume with double redundancy
** Start scanning metadata for a valid checkpoint
** Load and verify Segment Headers
** Load and verify Checkpoint Payload
** Load and verify Transaction Segment
** Load and verify Transaction Segment
** Incorporate 1 newer non-checkpoint transaction
** Load and verify Virtual Address Table
** Load and verify Segment Usage Table
** Load and verify Metadata Superblock
** Load and verify Logical Volumes B-Trees
   Unable to bootstrap transaction group 2815: cksum mismatch
** Continue scanning metadata for an older checkpoint
** Load and verify Segment Headers
** Load and verify Checkpoint Payload
** Load and verify Transaction Segment
** Incorporate 0 newer non-checkpoint transactions
** Load and verify Virtual Address Table
** Load and verify Segment Usage Table
** Load and verify Metadata Superblock
   In-progress volume maintenance
** Load and verify Logical Volumes B-Trees
   Unable to bootstrap transaction group 2814: cksum mismatch
** Continue scanning metadata for an older checkpoint
** Load and verify Segment Headers
   Unable to bootstrap transaction group 2813: cksum mismatch
** Continue scanning metadata for an older checkpoint
** Load and verify Segment Headers
   Unable to bootstrap transaction group 2812: cksum mismatch
   No valid commit checkpoint found
** The volume 97EFE039-8BB4-4907-8739-2D9636F68947 was found corrupt and can not be repaired

I have tried this: Repair a Mac OS X HFS+ Partition table – with no success. I also tried diskutil repairDisk /dev/disk0 and it failed because it couldn't create the EFI partition.

On Monday, Time Machine told me I needed to start a new backup, so of course I do not have a intact backup at the ready or I would've wiped it and restored.

Any ideas?

Answer 1

The partition map is completely valid - the CoreStorage stack is messed up though.

After creating a CoreStorage stack (e.g by enabling FileVault) the CoreStorage logical volume group should contain at least one physical volume, one logical volume family and a logical volume.

In your case the last two are missing due to CS stack corruption. The output of diskutil cs list in your question should also show a logical volume family and a logical volume.

In rare cases this may be repaired by booting to (Internet) Recovery Mode and opening Terminal in the menubar > Utilites:

Check the CS stack:

fsck_cs /dev/rdisk0s2

Repair it:

diskutil repairDisk /dev/disk0

---

If the latter fails restore your main volume using a current Time Machine backup. If you don't have a backup dd disk0 to a raw image and hope that someone comes up with a solution to repair or recover filevaulted data. I learned a lot about FileVault here - check the links (e.g. Infiltrate the Vault: Security Analysis and Decryption of Lion Full Disk Encryption) there also!