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So here´s what happened:

1 - I have an Imac and was trying to downgrade it from High Sierra to El Capitan by trying to force its installation manually. That corrupted the OS system files and I could not start the Imac.

2 - Then I created a bootable Ubuntu 18.04 LTS into a pendrive and am booting the Imac that way. While Ubuntu does list the drive, it cannot mount it. Therefore, I cannot backup the files to try and reinstall the mac OS again.

So, How do I get to mount the Apple SSD in order to backup my files ?

It´s an 1.0 TB Disk Apple SSD GPT partition, and the imac does not have access to internet, so anything I might need to install in order to fix this i have to get from another computer and use a flashdrive to transfer to the mac.

Hopefully i made myself clear enough, not a code expert so looking forward to the simplest solution to this.

EDIT: Here are some things I've tried:

sudo fdisk -l
Disk /dev/sda: 931.9 GiB, 1000555581440 bytes, 1954210120 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt

Device      Start        End    Sectors   Size Type
/dev/sda1      40     409639     409600   200M EFI System
/dev/sda2  409640 1954210079 1953800440 931.7G unknown

ubuntu@ubuntu:~$ sudo mount /dev/sda2 /mnt/mydrive mount: /mnt/mydrive: wrong fs type, bad option, bad superblock on /dev/sda2, missing codepage or helper program, or other error.

root@ubuntu:~# sudo mount -o force -t hfsplus /dev/sda2 /mnt/mydrive mount: /mnt/mydrive: wrong fs type, bad option, bad superblock on /dev/sda2, missing codepage or helper program, or other error.

`root@ubuntu:~# sudo blkid /dev/sda1: LABEL="EFI" TYPE="vfat" PARTLABEL="EFI System Partition" /dev/loop0: TYPE="squashfs" /dev/loop1: TYPE="squashfs" /dev/loop2: TYPE="squashfs" /dev/loop3: TYPE="squashfs" /dev/loop4: TYPE="squashfs" /dev/loop5: TYPE="squashfs" /dev/loop6: TYPE="squashfs" /dev/sdb1: LABEL="Ubuntu 18.04 LTS amd64" TYPE="iso9660" PTTYPE="dos" /dev/sdb2: SEC_TYPE="msdos" TYPE="vfat" /dev/sda2: PARTLABEL="Customer"

ubuntu@ubuntu:~$ chmod 777 /mnt/mydrive chmod: changing permissions of '/mnt/mydrive': Operation not permitted

root@ubuntu:~# dmesg | tail [15973.657824] hfsplus: unable to find HFS+ superblock [16676.299567] hfsplus: unable to find HFS+ superblock [16678.938532] hfsplus: unable to find HFS+ superblock [16692.359656] hfsplus: unable to find HFS+ superblock [16698.538832] hfsplus: unable to find HFS+ superblock [17648.524471] usb 1-6: USB disconnect, device number 12 [17906.084770] hfsplus: unable to find HFS+ superblock [18851.170154] hfsplus: unable to find HFS+ superblock [20157.836826] hfsplus: unable to find HFS+ superblock [20311.030734] hfsplus: unable to find HFS+ superblock

SurvivalMachine
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justme
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1 Answers1

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Start gnome-disks there you can get the device adress /dev/XXX. (For example: /dev/sda1).

Then you can try to mount it in the terminal. If you fail, you can post the errormessage and we can help you better ;-)

mkdir mnt_ssd
sudo mount /dev/XXX mnt_ssd/

Edit: It seems your superblock has some issues.

You can try to mount with an offset

sudo mount -t hfsplus -o ro,offset=$((512*409640)),sizelimit=$((512*1953800440)) /dev/sda /mnt/mydrive

If this wont work, i recommend to do a copy of the disk with sudo dd if=/dev/sda2 of=/somewhere/you/have/enough/space/disk.dd

Source: Can't mount HFS+ drive, bad superblock?

Boba Fit
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