Attempted to install Linux on my MacBook Pro 15" 2015 one day for school, but then the install failed and I had a GRUB issue similar to this: How do I recover/fix my OS X partition?.

Weirdest part was that before this I was able to boot into macOS Catalina just fine, and then after taking a look at Disk Utility (noticed swap partition exists, but not ext4) and shutting down (and then rebooting), the drive disappears.

Being shocked, I thought that deleting the Linux partition would solve my problems. WRONG (don't ask why plz). I formatted it to FAT32, then realized that did nothing. The linux partition(s) should be around 115 GB (since I allocated 40 GB for swap and 75 GB for Linux - tho I could be wrong). So, then I combined those two partitions and had a ~110 GB FAT32 partition.

I went into recovery ALT+CMD+R, and the drives couldn't be repaired.

I followed these directions: MacOS Disk Partition FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF

However, I realized that I typed in the incorrect start and size for all of my partitions and I don't remember the size of original partitions. Now I'm just stuck wondering how I could recover the data off my drive.

My main issue is after running gpt destroy ..., how would I know the original contents and can I still recover my files?

In Disk Utility, I wiped the FAT32 partition and replaced it with APFS, but the mac partition will not mount.

I'm also quite bad with terminal commands, but I'm willing to type whatever is necessary to get the data from my computer, since there's a lot of schoolwork on it.

I'm using an OWC Aura Pro 2 TB SSD, and I'm wondering if this could also be a factor.

Output of diskutil list and gpt -r show disk1:

diskutil list

gpt -r show disk1

Edit: scratch that, I only see disk1s1 now, and that the other two partitions are gone completely:

enter image description here

enter image description here

Edit2: heres the output from running commands from klanomath (thank you!)

-bash-3.2# export LC_CTYPE="ASCII"
-bash-3.2# dd if=/dev/disk1s2 bs=512 count=1 2>/dev/null | vis -wc; 
'\M^Q9\r\M-/\^X\s\M^E\^A\0\0\0\0\0\0\0\M-7q\a\0\0\0\0\0\^A\0\0\M^@\0\0\0\0NXSB\0\^P\0\0\M-3\M-mA\^Z\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\^B\0\0\0\0\0\0\0T\M-6\^\\M-C\M-k\M-\Kk\M-(bL\M-"\M^D?\M-^Z\M-d\M-4\a\0\0\0\0\0\M-8q\a\0\0\0\0\0\^X\^A\0\0\M^\l\0\0\^Z\M^M\^B\0\0\0\0\0~\s\^B\0\0\0\0\0\M-L\0\0\0\^R\^_\0\0\M-J\0\0\0\^B\0\0\0\M-~\^^\0\0\^T\0\0\0z\M-.\a\0\0\0\0\0\M-xA\s\0\0\0\0\0\^A\^D\0\0\0\0\0\0\0\0\0\0d\0\0\0\^B\^D\0\0\0\0\0\0\^F\^D\0\0\0\0\0\0\b\^D\0\0\0\0\0\0\n\^D\0\0\0\0\0\0\f\^D\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0-bash-3.2# dd if=/dev/disk1s2 bs=512 count=1 2>/dev/
  • 1. Currently disk0 is your Recovery volume (which doesn't require an EFI) 2. Please enter export LC_CTYPE="ASCII" then dd if=/dev/diskXsY bs=512 count=1 2>/dev/null | vis -wc; echo (with diskXsY the 2nd partition of the SSD; currently disk1s2) in the terminal. Add the output of the 2nd command as text here. You can access apple stackexchange with Safari in Recovery Mode (and your credentials here)!
    – klanomath
    Apr 13, 2020 at 7:27
  • @klanomath woah I didn't know that was even possible! the text is posted in edit2. thank you!!
    – tyboi
    Apr 13, 2020 at 18:04
  • The important part translates to 4e 58 53 42 00 10 00 00 b3 ed 41 1a 00 00 00 00 |NXSB......A.....|. This means 3,524,226,456 blocks(512) for the APFS container (~1.804 TB). The partition (disk1s2 in the screenshot 2) is too small - it should have the same size as the container!
    – klanomath
    Apr 13, 2020 at 18:14
  • To fix this you have to remove the second partition of the SSD and add it slightly larger: 1st step: gpt remove -i 2 /dev/disk1 2nd step: gpt add -i 2 -b 409640 -s 3524226456 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk1.
    – klanomath
    Apr 13, 2020 at 18:19
  • as soon as I saw ur previous (previous) comment without looking, I did that exactly and it worked!!!!!!! thank you so much! the drive was detected and I'm going to backup ASAP! thanks again!!!
    – tyboi
    Apr 13, 2020 at 18:23

2 Answers 2


The main partition of the SSD (disk1s2) and the APFS container have different sizes.

To fix this the partition disk1s2 has to removed and added again with the proper size - the size of the APFS container:

  1. The size of the partition disk1s2 is 3151589464 blocks (512 Bytes) (according to the gpt listing in screeenshot 2
  2. The size of the APFS container is stored in the superblock (1st block of disk1s2)

    To get the content of the superblock one can either use hexdump or in Recovery Mode vis:

    -bash-3.2# export LC_CTYPE="ASCII"
    -bash-3.2# dd if=/dev/disk1s2 bs=512 count=1 2>/dev/null | vis -wc; echo

    Result (relevant parts of the output only starting with NXSB):

    -bash-3.2# NXSB\0\^P\0\0\M-3\M-mA\^Z\0\0\0\0  

    which translates to

    -bash-3.2# echo -n 'NXSB\0\^P\0\0\M-3\M-mA\^Z\0\0\0\0' | unvis | hexdump -Cv
    00000000  4e 58 53 42 00 10 00 00  b3 ed 41 1a 00 00 00 00  |NXSB......A.....|

    here another working Mac is needed to execute hexdump.

    NXSB is the magic string of an APFS container. 0x00100000 reversed is the allocation block size (4096 Bytes) and 0xb3ed411a00000000 reversed (0x1a41edb3) is the number of allocation blocks (440528307). The size of the container in 512 Byte blocks is the number of allocation blocks * 8 = 3524226456.

  3. To adjust the partition size to the container size one has to remove it and add it in a second step slightly larger:

    gpt remove -i 2 /dev/disk1
    gpt add -i 2 -b 409640 -s 3524226456 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk1
  4. Verify disk and APFS container scheme: diskutil verifyDisk disk1 and diskutil verifyVolume diskX with diskX=the device identifier of the synthesized APFS container scheme.

I am sorry to hear that you are having this issue. Can you access macOS Recovery? If you can, that's great news!

If you can access macOS Recovery, then the first step would be to run First Aid on APPLE SSD/HDD, the Container Disk, and Macintosh HD. If the process fails, then that means that the data might not be recoverable. If you do manage to mount the disk, then that's good news!

If the OS drive mounts, then go to Disk Utility and type cd /Volumes/Macintosh\ HD then type ls. This will allow you to see if your data is still there.

If you can boot up on the macOS Drive again, then that's good and your repair process is complete! If not, then try reinstalling macOS from macOS Recovery. This will not delete your data. Then try booting up on it.

If none of these work, then the last thing that you can do is erase the APFS container, and reinstall macOS on Macintosh HD.

Good luck!

  • Yes I was able to access macOS internet recovery by running option, cmd, R. I've already attempted using first aid, and it doesn't work since it just gives me an error. my data seems to be there, but idk. Also, I don't want to do the last resort thing since this is a computer that I use for school and there's info I want to recover. The main issue is that I forgot the size of the partition after running "gpt destroy disk1". I know that for sure that disk1s1 has to be the EFI boot, but idk about the rest about disk1s2 (the drive) and disk1s3 (the linux swap partition that has been formatted).
    – tyboi
    Apr 13, 2020 at 3:41
  • The EFI is usually disk0s1 If APPLE SSD is disk0. disk1s2 is usually a volume within the APFS container (The preboot volume). Can you reinstall macOS or boot Single User mode? In single user mode, use fsck_apfs.
    – Todd
    Apr 13, 2020 at 4:39
  • I said earlier I can't do a reinstall since I don't have a backup of the original files, and don't want my files deleted. Also see imgur.com/a/5I7GAx7 (the edit2 i posted), EFI is in disk1, not in disk0. I'm also using an aftermarket nvme ssd (OWC ssd) which might also explain why my stuff isn't in disk0. Also in single user mode (CMD+R), my drives cannot be detected, probs due to the fact im using an OWC ssd.
    – tyboi
    Apr 13, 2020 at 4:56
  • You can do a reinstall of macOS on the startup volume without losing any data from Internet Recovery. Choose the reinstall macOS Option.
    – Todd
    Apr 13, 2020 at 19:22

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