Power Cut Out When Updating OSX From Mojave To Big Sur

[Grino]

I have a large problem

As the title describes my power cut out (faulty power cable) when I was upgrading from Mojave to Big Sur about a month ago. My 2015 Macbook Pro now won't load past the Apple logo and my Macintosh HD partition won't mount no matter which method I use. I have a second partition for the new OSX update which I have included a screenshot of after using iBoysoft Recovery to remove some important files.
Should I delete the APPLE SSD SD 512E MEDIA partition that High Seirra created?
Will FSCK or diskutil repairvolume fix my Mojave partition and will it be safe?

Does anyone know how I can fix this or what should read to learn how to fix this?

Thanks!

 

[Fishrrman]

If nothing else works...
Sounds to me like you might have to erase the entire drive and start over.

Command-OPTION-R will boot to internet recovery and install Big Sur, I believe.

Command-SHIFT-OPTION-R will boot to internet recovery and install El Capitan, I think (this is the option to restore the original version of the OS that shipped with the Mac, and for 2015 it was El Cap).

If you decide to use either of the above options, go to disk utility.
Then... VERY IMPORTANT -- go to the view menu and choose "show all devices".
Then look to the list on the left -- the topmost item is the drive itself.
You need to click on that and then click the "erase" button.

Of course, if you do this, you ERASE EVERYTHING that was on the drive.
So... without a backup, you could be in trouble.

But... it might be the only way to "get things going" again.

 

[Grino]

Thank you for the reply

I have files on the drive I unfortunately needed to remove and these are not working properly when checking on a another machine so I need to try and save these if possible (for now) and avoid formatting.

 

[pmiles]

There is a real possibility that you won't even be able to format the drive from any machine if you can't even get it to show up.

You can always take the drive out and replace it with a new drive. Your data will remain as it is on the faulty drive forever that way, but you will have your computer back in the meantime.

Then you can farm the bad drive out to some data recover outfit and spend a small fortune to retrieve a small portion of what is on it... if that much. Data recovery is never an absolute.

 

[Grino]

Could I boot the drive using a bootable USB with a copy of Mojave on it and recover files easily this way? In fact could I potentially permanently boot the Macbook this way?

 

[hammie14]

Could I boot the drive using a bootable USB with a copy of Mojave on it and recover files easily this way? In fact could I potentially permanently boot the Macbook this way?

Yes you could install any version of OSX / macOS on a USB stick and boot from the USB drive (or usb HDD). To do this you would power up the MacBook Pro and hold down ALT and then point to the macOS volume on the USB.

Once macOS has booted /setup you should be able to see your old SSD and recover your files, depending on if you had FileVault enabled. If you had FileVault enabled and the drive is corrupted then you maybe in trouble.

 

[Grino]

If this is so easy to do why is there recovery software that works in Recovery Mode? My Macbook Pro is from 2015 running Mojave so I don't think it will have Filevault.

 

[Grino]

A bootable USB will install files of the OSX onto the SSD I'm trying to remove files from and potentially overwrite files I'm trying to recover no? What am I missing?

 

[Apple_Robert]

If you delete the Apple SSD (with numbers drive) that will erase and then you can rename it and that will get it to mount.

 

[Grino]

I'm not trying to mount the Apple SSD volume, if anything I would be trying to mount the AppleAPFSMedia volume as this has my data and original Mojave installation (volume as shown in my screenshot). What am I missing?