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MacBook Pro 2015, 256GB SSD disk

I have created a second partition on my disk to try Linux. Everything was fine, but at some point, macOS disappeared from the boot menu.

After some googling and trying some things, I thought it was a problem with the boot manager. I installed rEFInd but it didn't help. So I tried torecover everything using recovery mode. But there was no option to reinstall macOS on the first partition. I could only erase it. I also couldn't mount it to macOS Recovery.

I installed OS X 10.10 Yosemite (base for my MacBook) on the second partition and updated it to macOS 10.14 Mojave (to be able to mount that first APFS partition). But I still can't mount it:

daniils-MacBook-Pro:Volumes daniilkk_yose$ sudo mount -t apfs /dev/disk0s2 plz/
mount_apfs: mount: Inappropriate file type or format

Also, diskutil outputs many F's instead of type and name:

daniils-MacBook-Pro:Volumes daniilkk_yose$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2: FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF               129.2 GB   disk0s2
   3:                 Apple_APFS Container disk1         121.6 GB   disk0s3

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +121.6 GB   disk1
                                 Physical Store disk0s3
   1:                APFS Volume disk1s3                 12.8 GB    disk1s1
   2:                APFS Volume Preboot                 43.1 MB    disk1s2
   3:                APFS Volume Recovery                510.4 MB   disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4

Disk Utility doesn't show this partition at all:

Disk Utility

Is there a way to mount it and get my data back?

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2
  • Most linux installers have a command you can use to fix this sort of problem.
    – David Anderson
    Dec 2, 2020 at 14:28
  • What kind of a command?
    – daniilkk
    Dec 3, 2020 at 9:29

2 Answers 2

Reset to default
0

This happened to me too (3 times actually). I fixed it like this:

  • Boot into a LiveCD containing fdisk or gdisk (I used gdisk so I can’t give fdisk instructions)
  • Type gdisk /dev/sdX, where X is your SSD. You can use gdisk -l /dev/sd* or fdisk -l /dev/sd* to find it. It’s the one with the partition with the FFFF spam.
  • Type the following:
t
2
af0a
w
y

Explanation: t for "set type of partition", 2 for the second partition (disk0s2), af0a for "Apple APFS", w for write, and y to confirm.

  • Reboot, you will be able to boot MacOS again.
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-1

I've had exactly the same issue on an older MBP running 10.13.6. I've tried twice to work around it and got your problem.

In the end (both times) I had to do a recovery using internet recovery (option-command-r) and then restore my stuff from Time Machine. I looked at rEFInd but didn't install it, so I can't say how to drive it.

It seems that APFS doesn't like to be messed with. I'm looking at dropping the APFS and just living with the old journaled FS as a fixed size partition.

After that, I figure I can tinker with the EFI partition until I get it right.

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