Reinstalling OS, can't erase Mac HD

[atrophy08]

TLDR; Boot from install disk for High Sierra, Disk Util won't erase MacHD inside SSD container for clean install, Installer app says Mac HD is locked, never had FileVault engaged and it doesn't show core in diskutil list.

I have tried to erase Mac HD but it never moves progress bar and I have had it going keeping screen awake for over two hours. I am not sure if I should erase via terminal because I don't know what disks are safe to force erase. My iMac is a mid 2017 21.5" that came with High Sierra. I have tried beta Mojave and it crumpled my system.

My disk list is as follows: disk0 (internal) GUID-scheme Apple-APFS container disk2, 28gb; disk1 (internal, physical) GUID-scheme Apple-APFS container disk2 1TB; disk2 (synthesized) APFS Scheme APFS Volume, Macintosh HD, 268 Gb, Preboot, 22mb, Recovery, 509mb, VM, 2.1 gb, and then the installer thumb drive that I booted in.

I have to clue what to do - I am intermediate users but know I am past the simplicity that I thought installing from a boot drive or from internet recovery. I had time machine backups but that disk had electrical damage from a storm. Someone please advise.

 

[Weaselboy]

Click two spots up there where it says Apple SSD SM.... then click erase to format the whole disk.

 

[atrophy08]

Click two spots up there where it says Apple SSD SM.... then click erase to format the whole disk.

I was able to erase this disk - it was only 26 gigs and then was able to force erase the 1tb drive to get it to be my boot drive. Any suggestions as of what to do with that 26gig partition is it for recovery?

 

[atrophy08]

It was a fusion drive and that was the ssd - is there anyway to restore the fusion/hd combo. I’m not sure exactly how they were set up by they were meant to store some data for quick use and recent files. Just posing the question - may ask in another post

 

[Funsize93]

The fusion drive and software self manages your most important data and the OS to be stored on the SSD, it will store other data on the HDD. It looks like your fusion drive has split, i dont know if it was intentional on your behalf or maybe a corruption or a hardware failure. https://support.apple.com/en-au/ht207584 shows how to fix a split fusion drive. If you cant fix it with terminal commands then you may have a hardware failure with your internal HD.

edit: disregard this if the SSD and HDD are entirely separate physical drives.

 

[Weaselboy]

It was a fusion drive and that was the ssd - is there anyway to restore the fusion/hd combo. I’m not sure exactly how they were set up by they were meant to store some data for quick use and recent files. Just posing the question - may ask in another post

It does look like you somehow split the Fusion drive.

https://forums.macrumors.com/posts/22923054/

Follow the steps in my posts #6 and #14 at this ^ link to rebuild the Fusion drive and start over.

 

[atrophy08]

Thanks to you both! I followed the Apple support page and got it done really quick. Thanks for taking care of the issue!!! https://support.apple.com/en-us/HT207584