Recover unmountable partition on external drive (OS X)

Using TestDisk to repair the filesystem
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Posts: 1
Joined: 28 Oct 2015, 04:19

Recover unmountable partition on external drive (OS X)

#1 Post by grossi419 »

I screwed up my backup external hard drive. I was attempting to make a bootable USB in terminal on El Capitan. I was hoping I could install the bootable part on a partition of the USB drive so I split the USB drive. This would have created the disk identifiers disk#s0, disk#s1, disk#s2, and disk#s3 on the flash drive.

The problem happened when I used terminal to put the ISO onto the disk#s3 partition. I stupidly fat-fingered the disk# and entered the disk# of my backup external, but I still had the s3 suffix.

The external HDD didn't have any partitions to OS X only read identifiers s0, s1, and s2. s2 is the drive with the data and formatted HFS. Now it reads s0, s1, and s3 and is currently unmountable.
Disk Util List screenshot. LaCie is the drive in question (it was named differently before, if that matters).
Disk Utility repair error details screenshot

Tesk Disk partitions
Test Disk superblock of the partition I want to recover

How can I recover the partition? Is it as simple as changing the disk identifier? How would I do that? Or did my attempting to make a bootable drive on a nonexistent partition screw stuff up?

I do have a Windows machine available with a free 1TB hard drive formatted in NTFS if I need to copy the data to a new hard drive via direct ethernet connection. This drive has my backups on it, too, so keeping the file structure is pretty important to me.

Thank you in advance!