APFS system volume recovery after Macbook Air logic board failure

Discussion in 'Mac Basics and Help' started by spaceguns, Aug 13, 2019.

  1. spaceguns macrumors newbie


    Aug 13, 2019
    I only have partial information, and do not 100% know the exact OSx version or how full the drive was, but I think it was pretty topped out. No recent backups, important data, and I have already put the fear of god into them regarding backups so this doesn't happen again. They have a several months old timemachine backup available so if there may be something useful there like a partition table or encryption key I need I may be able to get access to it.

    The set up, steps taken and how we got this far:
    -Friend's 2015 Macbook Air stopped turning on. May have had a bad shutdown involved. Dead logic board.
    -Drive Enclosure is obtained. The drive would not successfully boot into any macs at the Apple store. Genius Bar may or may not have run some commands to try and recover things. Report that part of the SSD that managed FileVault is probably damaged.
    -Friend's university tech shop takes a look with no luck.
    -They stress how important some of their research data is, I refer them to Drive Savers out of an abundance of caution.
    -Drive Savers tries to hook it into a system (??), says it isn't working, sends them on their way within 15 minutes or so.
    -Bottom line, the usual boot off of it on a different mac, etc troubleshooting isn't working.
    -I take pity on them and have taken this on as a side project, believe this is an encrypted APFS drive.
    -I manage to capture a seemingly 100% good 500GB disk image, and mirror to a 2TB external drive, directly off the bad drive in the enclosure on an Ubuntu system using ddrescue. For anyone else going through this with a drive that keeps dropping connection, try a powered USB hub.

    ddrescue commands used

    sudo ddrescue -f -n -c 4096 /dev/sdc "/media/spaceguns/TOSHIBA EXT/RescueImage1.dmg" "/media/spaceguns/TOSHIBA EXT/mapfile1.txt"
    sudo ddrescue -d -f -r3 -c 4096 /dev/sdc "/media/spaceguns/TOSHIBA EXT/RescueImage1.dmg" "/media/spaceguns/TOSHIBA EXT/mapfile1.txt"
    sudo ddrescue -d -f -r3 -c 4096 /dev/sdc /dev/sdb mapfile.txt
    No bad sectors or errors on both, a quick look at the image in a hex editor and yep, stuff is in there alright. Have a backup of the dmg just in case.

    Feeling a new level of confidence that I won't fry the last hope we have of getting this data back by hammering it with attempts, it's time to jump on my wife's Macbook Pro and see what we can see. Unfortunately, not being a mac guy, I am hitting some walls, probably caused by my own ignorance of the underlying system and available commands. I am comfortable at a command line, but I am not a mac user.

    Mac Attempts and command results:

    DISK UTILITY File>Open Disk Image>RescueImage1.dmg

    Hangs and very briefly it appears on the left showing the following then it immediately disappears


    Hooking the cloned drive up [​IMG][​IMG]

    Click Mount on disk3s2 and nothing happens, no feedback

    File->Get Info on disk3s2

    Volume type : APFS Physical Store
    BSD device node : disk3s2
    Connection : USB
    Device tree path : IODeviceTree:/PCI0@0/XHC1@14
    Writable : No
    Is case-sensitive : No
    Volume capacity : 500,068,036,608
    Owners enabled : No
    Is encrypted : No
    Can be verified : Yes
    Can be repaired : Yes
    Bootable : No
    Journaled : No
    Disk number : 3
    Partition number : 2
    Media name :
    Media type : Generic
    Ejectable : Yes
    Solid state : No
    S.M.A.R.T. status : Not Supported
    Parent disks : disk3

    File->Get Info on AppleAPFSMedia

    Volume type : Uninitialized
    BSD device node : disk4
    Connection : USB
    Device tree path : IODeviceTree:/PCI0@0/XHC1@14
    Writable : No
    Is case-sensitive : No
    Volume capacity : 500,068,036,608
    Available space (Purgeable + Free) : 0
    Purgeable space : 0
    Free space : 0
    Used space : 500,068,036,608
    Owners enabled : No
    Is encrypted : No
    Can be verified : No
    Can be repaired : No
    Bootable : No
    Journaled : No
    Disk number : 4
    Media name : AppleAPFSMedia
    Media type : Generic
    Ejectable : Yes
    Solid state : No
    S.M.A.R.T. status : Not Supported

    Disk Utility First Aid Results

    Running First Aid on “AppleAPFSMedia” (disk4)
    Fixing damaged partition map.
    Invalid disk.
    Operation failed…
    Running First Aid on “” (disk3s2)
    Repairing storage system
    Performing fsck_apfs -y -x /dev/disk3s2
    Checking the container superblock.
    Storage system check exit code is 0.
    Operation successful.
    Still no mount on disk3s2. I think I have exhausted my Disk Utility GUI options so now it is off to the command line! This will all be on the cloned drive. I am trimming out references to the other system drives for easy of reviewing.

    Janes-MacBook-Pro:~ John$ diskutil list
    /dev/disk3 (external, physical):
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *2.0 TB     disk3
       1:                        EFI EFI                     209.7 MB   disk3s1
       2:                 Apple_APFS Container disk4         500.1 GB   disk3s2
    /dev/disk4 (synthesized):
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      APFS Container Scheme -                      +ERROR      disk4
                                    Physical Store disk3s2
    Janes-MacBook-Pro:~ John$ diskutil apfs list
    APFS Containers (2 found)
    +-- Container disk1 (trimmed data)
    +-- Container ERROR -69808
       APFS Container Reference:     disk4
       Size (Capacity Ceiling):      ERROR -69620
       Capacity In Use By Volumes:   ERROR -69620
       Capacity Not Allocated:       ERROR -69620
       +-< Physical Store disk3s2 0804ED4C-B212-4BF2-B475-6026969AE826
       |   -----------------------------------------------------------
       |   APFS Physical Store Disk:   disk3s2
       |   Size:                       500068036608 B (500.1 GB)
       +-> No Volumes
    Janes-MacBook-Pro:~ John$ distill mountDisk /dev/disk3s2
    One or more volume(s) failed to mount
    Janes-MacBook-Pro:Documents John$ diskutil mountDisk disk4
    Volume(s) mounted successfully
    If that actually did something I am not aware. Nothing additional seemed listed or mounted anywhere. I ran the below gpt commands, unmounted disk 4, and ran them again and checked Disk Utility/finder for any changes. Meanwhile assuming we are not actually mounting.

    Janes-MacBook-Pro:~ John$ sudo gpt show disk3
          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   976695384      2  GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
       977105024  2929858399         
      3906963423          32         Sec GPT table
      3906963455           1         Sec GPT header
    Janes-MacBook-Pro:~ John$ sudo gpt show disk3s1
       start    size  index  contents
          0       1         MBR
          1  409599         
    Janes-MacBook-Pro:~ John$ sudo gpt show disk3s2
         start       size  index  contents
             0  976695384         
    Janes-MacBook-Pro:~ John$ sudo gpt show disk4
         start       size  index  contents
             0  122086923       
    Janes-MacBook-Pro:~ John$ diskutil apfs unlockVolume /dev/disk4
    /dev/disk4 is not an APFS Volume
    Same result for all /dev/disk* attempts

    Janes-MacBook-Pro:~ John$ diskutil verifyVolume disk4
    Started file system verification on disk4
    Verifying storage system
    Performing fsck_apfs -n -x /dev/disk3s2
    Checking the container superblock
    Storage system check exit code is 0
    Finished file system verification on disk4
    Seemed to result in no changes

    Janes-MacBook-Pro:~ John$ diskutil verifyDisk /dev/disk4
    Janes-MacBook-Pro:~ John$ diskutil repairDisk /dev/disk4
    both returned

    Unable to verify this whole disk: A GUID Partition Table (GPT) partitioning scheme is required (-69773)
    Restart, option key at Chime = Clone drive does not appear

    tried iBoysoft
    iBoysoft sees it but does not accept the password and has no option to utilize recovery key (I did try this in addition to the password)


    Tried Recovery Studio Pro on Win10 and it noted that no apfs keys were found after a full scan, which is why I am wondering if some item required to decrypt is wiped and if it might be able to be recovered and placed back in there from a backup.

    I am just lost at what to do from here, or what may be missing. I assume getting the volume to show back up to where I can see it in terminal is the next step but I don’t know how to approach it.

    Disclosure - after the above I did try some hail mary commands butI don’t mind recloning a fresh drive copy to try and work further on this.

    Also worked with the that wouldn't mount using hdiutil but running out of characters here. Can recap if it may be helpful.
  2. casperes1996 macrumors 68040


    Jan 26, 2014
    Horsens, Denmark
    Hm. So, APFS works by having both a container and actual volumes, as you may be able to snuff out from the digging you've done. Where a "traditional" file system just writes a volume directly to its partition in the partition map, APFS writes a container - sort of like its own partition map inside the partition it's given. From the container, which can span multiple drives, it can create volumes. Thus it can resize the volumes within the container without any issue or messing with the partitioning. - Very similar to ZFS in many ways.

    It seems like whilst you've extracted a valid container, and perhaps data, the whole volume group inside the container is messed up with ERROR all over the shop. The information needed to recreate the volume details are likely present in the old backups, though whether the file system index is affected by the errors is unknown. You may be able to create a new, empty volume of the same information; Size, drive number and such - and see in your hex editor if there's sufficient similarity between it and the beginning sectors if the clone that you can mirror it and get somewhere; I don't know if this part of the drive information is also under any form of encryption.

    I can't think of any command or anything that you haven't already tried that could help you out though I'm afraid.
    diskutil ap
    gets you a list of all APFS related commands (meant to be publicly visible).

    If I were to get on the front of encryption, since the volume header info seems lost, I think there's a good chance the volume doesn't actually know it's encrypted with a password. Even if given the correct password to unencrypted the data it wouldn't be able to verify the password. It might still be able to decrypt the data on the drive, but the drive wouldn't know it was valid, and can't discern the unencrypted and encrypted data. - This issue is perhaps what you ran into with the recovery software you mentioned.

    I have no good ideas I'm afraid, but it's an interesting problem and I'd love to hear it if you find a solution.
    APFS is still a relatively new file system, meaning that the field of data recovery has a lot less experience with it, than if the lost data was, say FAT, EXT4 or even NTFS. Hell, or JHFS+
    --- Post Merged, Aug 13, 2019 ---
    Oh, and can I just say... TARDIS is an excellent volume name, especially if it hosts Time Machine backups. I've just watched a boatload of Who myself. Finished rewatching the 2005 era show and went right back to William Hartnell. Lovely indeed.
    Good luck with the data recovery!
  3. chown33, Aug 14, 2019
    Last edited: Aug 14, 2019

    chown33 Moderator

    Staff Member

    Aug 9, 2009
    An old Time Machine backup is very unlikely to contain a partition table or an encryption key. TM backups are made by walking files and dirs using the file-system. Both partition tables and encryption keys are at a level far lower than that.

    Depending on your programming skills, it's possible that poking around in the innards of the encrypted data will give more details. As a result of a completely separate discussion in this thread:

    I learned that the researchers who dug into FileVault2 have published their software, which allows decoding FV encryption on non-Mac systems.

    Here's the PDF paper that discusses the details:

    Their library is listed at:

    which appears to be a dead link.

    Googling finds this:

    The lib may be able to help directly, if it lets you determine exactly which parts of the FV decryption process have been damaged. If not, it may take some programming to turn it into a tool for poking around at a non-working FV disk.

    I should note there are several layers here. One is the GPT partitioning scheme. The next is FileVault. After that is the CoreStorage container, whose contents are encrypted, and finally APFS. If an earlier layer is damaged, then later ones will be unobtainable, especially if FV's key storage management has been lost or damaged.

    FV is designed so that losing the key makes all the encrypted data inaccessible. If this weren't so, then it would be weak protection.
  4. NoBoMac Moderator


    Staff Member

    Jul 1, 2014
    What @chown33 said. But with the caveat that since APFS, there won't be a CoreStorage component in play.

    But from what little I've seen re: APFS, FileVault will work in a similar way in that there probably is (was?) a key saved in the header for the APFS container, which then runs a similar decryption process of decrypt keychain, decrypt secondary key, decrypt volume key, decrypt drive.

    One thing I've seen mention of, but nothing concrete: might be another layer of encryption, at the file level. Similar to how iOS encrypts files and filesystem. Which would make some sense, as APFS went to iOS first, and that filesystem was already APFS-ish.

    Some details on how things work in iOS found here: https://www.apple.com/business/docs/site/iOS_Security_Guide.pdf
  5. spaceguns thread starter macrumors newbie


    Aug 13, 2019
    First off, thank you all for taking the time to give such thorough feedback. I will be reading/reviewing everything in the links and I appreciate the help on my journey of learning the unique apple filesystem and encryption methods.

    What I am tracking as possible hail mary leads are
    1. Research and see if there is a possibility that Volume data may be in a time machine backup, but as chown33 stated this is unlikely. I haven't dug into time machine at all (not a mac user) but I will look at documentation and my wife's time machine to see if there is any data and pathway to essentially rebuild a Volume off of data backed up to Time Machine. If time machine just does a dir walk and copies files and doesn't copy any type of system/partition info then that's a dead end. Honestly while I am generally comfortable screwing around with low level stuff I have never had to really dig into how Volume data works at that level.

    2. If I can rebuild the volume and have all the keys exactly where they need to be I can find where the volume data ends/any other critical part then maybe successfully copy the encrypted data over the remainder, splicing them together.

    If I am tracking right to have any chance I would need FileVault and APFS keys. I know if the keys are gone, it's a dead end unless there is some underlying flaw in the later discovered in the encryption implementation.

    Next step is to read and digest the documentation for https://github.com/libyal/libfvde to get a better handle on how the underlying works and see if there is anything I can extrapolate from it, then build from source and see if it gets any further.
    https://github.com/libyal/libfvde/blob/master/documentation/FileVault Drive Encryption (FVDE).asciidoc

    Also, thank you for the compliments on TARDIS, yes, it is my wife' s Time Machine drive and I thought it was pretty clever. For an additional laugh she made a vinyl pattern and decorated it https://imgur.com/XdjbQxm

    For anyone else following along. Stress the 3-2-1 Backup Rule to everyone (yes, including offsite, local backups don't help if your house burns down with everything in it), along with testing those backups and hammering in how extra critical it is if they are using full disk encryption as that can greatly frustrate recovery efforts.
  6. Fishrrman macrumors P6


    Feb 20, 2009
    I'll make it brief:
    If "Drivesavers" says they can't "get at" the data, the chances aren't good at getting it back.

    I suggest you give your wife a tutorial in the concept of "backing up".
    I STRONGLY SUGGEST that you DO NOT use Time Machine for this.

    Use either CarbonCopyCloner or SuperDuper instead.
    And... keep at least ONE of the backups "in the clear" (NO encryption).
    If necessary, keep it locked in a safe.

    As you have discovered, when things go wrong, getting data back is a chore.
    But when it's strongly encrypted -- it can make things worse to... impossible.
  7. casperes1996 macrumors 68040


    Jan 26, 2014
    Horsens, Denmark
    Time Machine has its own file system, and AFAIK currently doesn't even support being on an APFS Volume yet. Time Machine is still HFS+ only as my knowledge goes. Thus, it seems like it probably is just a file walk, but one based on deltas.

    I think it's a long shot, but it's the best thing I can think of yeah.

    Absolutely brilliant. Or as Christopher Eccleston, the 9th Doctor would say, Fantastic.

    ... I used to have my data on 3 different drives; Some things in iCloud too but I don't count that... Over the Summer I've had 2 drives die almost at the same time. Got one replaced under warranty
  8. Mr_Brightside_@ macrumors 68040


    Sep 23, 2005
    The failed drive is a friend's, OP has been working off his wife's Mac.
  9. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California

    "Carbon Copy" is actually a quite bad idea. Why? Here is the scenario where CCC fails. You are editing this novel you are writing and you stop and back it up using CCC. Now you have a good copy. Then you accidentally delete Chapter Three while writing Chapter Five but don't notice your mistake. But it is OK you have a backup. Now after finishing Chapter five you do another backup and overwrite your previous backup. Chapter three is now gone forever.

    If you had used Time Machine you have EVERY version of your novel automatically saved with no data overwritten.

    Yes, incremental backups are hard to understand and CCC is conceptually simple so people like it. But you REALY need to do incremental backups and TM makes this easy.

    There are many other ways CCC can fail. But in every case it has the same form: You do a backup, everything is OK. Data gets corrupted and you do another backup and kill you only good backup by writing corrupted data over op of it.

    The lesson learned is to NEVER overwrite a backup. Keep it "forever", this means for YEARS. TM does this automatically.

    Some people thing TM saves data is some obscure format. No. It simply copies the files using the file system. The saved files are just like if you copied them using the finder. But with one difference: It only copies the files that changed.

    The first time you run TM it copies every file. The next time it only copies files that have changed. That's it. Over time if you edit a lot of files the multiple copies start taking a lot of room. So TM will thin out the number of redundant files by keeping only daily or weekly copies of the oldest files rather than hourly copies.

    When buying a disk for TM, buy one that is at least twice as large as the amount of data you want to back up.

    TM should be you first level backup and just let it run and do its hourly backup.

    But overall the rule of thumb is that you always need to be sure these rules are followed:
    1) the data exists in at least three physical devices even when a backup operation is in progress.
    2) the data exits in at least two geographic locations even when a backup operation is in progress.
    The above is dead-minimum. If the data is really important then add more copies in more locations

    A simple way to do this is to use TM and a cloud backup service. Run both of these continuously. I used Backblaze for cloud backup. It runs continuously and sends data off to a secure location within some minutes of saving the file. The cost is only $6 per month for unlimited storage. Then in addition to TM and the cloud. You might periodically use something like CCC to make a copy and rotate this with another copy you keep off site.

    Never overwrite backup data.
  10. Mr_Brightside_@ macrumors 68040


    Sep 23, 2005
    Isn't this what CCC Safetynet does?
  11. spaceguns thread starter macrumors newbie


    Aug 13, 2019
    As a minor update while I have the fun times of exploring the ins and outs of the file system before I throw in the towel once I confirm any of the encryption keys I need are well and truly gone.

    I was able to extract what I believe the be the full encrypted EncryptedRoot.plist.wipekey file via hexeditor. There's enough in the xml that matches up with what I would expect to see in the file with PassphraseWrappedKEKStruct (x2), and KEKWrappedVolumeKeyStruct being sdauibfasbubi gobs of encrypted text. Also EFILoginGraphics is a mess of data but this was not mentioned in the paper as important to the encryption.

    Also using SleuthKit on the dmg
    GUID Partition Table (EFI)
    Offset Sector: 0
    Units are in 512-byte sectors
          Slot      Start        End          Length       Description
    000:  Meta      0000000000   0000000000   0000000001   Safety Table
    001:  -------   0000000000   0000000039   0000000040   Unallocated
    002:  Meta      0000000001   0000000001   0000000001   GPT Header
    003:  Meta      0000000002   0000000033   0000000032   Partition Table
    004:  000       0000000040   0000409639   0000409600   EFI System Partition
    005:  001       0000409640   0977105023   0976695384   Macintosh HD
    006:  -------   0977105024   0977105059   0000000036   Unallocated
    Next step from the paper would be "The EncryptedRoot.plist.wipekey file is encrypted using AES-XTS (details later) with an all-zeros tweak key, but the encryption key is easily available in the header (first block) of the CoreStorage volume (see table 2 in Appendix)"

    Anyone have any recommendations for finding my way to the first block of the CoreStorage volume or nearby or how to maybe grep or regex this thing out of the image?

    I am traveling so only have a windows machine and minimal time and don't want to mess with mounting to vm's at the moment but I figured I would update those to looked to help and see if anyone had any tips to get to the first block of the CoreStorage volume while I continue to research. Meanwhile running full image searches for some obvious-ish terms that might dial me in since some google-fu on this has failed me, or I have failed it.

    After I have exhausted my abilities I will shoot the researchers an email to see if there is anything I am missing before calling it.

    Also, yeah, thanks for pointing out this is a friend's drive. My household is already on cloud with some versioning (tested lightly, although I should test more extensively) and periodic offline local backups. Although it could always be better (can never have enough).

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10 August 13, 2019