Can't delete APFS volume! ...rendering MacBook unusable.

Run the Apple Diagnostics.

You want to erase the physical drive, but with recent versions of Disk Utility the physical drive is hidden from view by default. You need to click on "View" within Disk Utility and select "Show All Devices" before the physical drive is shown on the left pane of Disk Utility. Here is an Apple article with details:

https://support.apple.com/en-us/HT208496

If for some reason you are booting to an older macOS installer (pre-10.13), then you will need to click on the "Partition" tab within Disk Utility and select "1 partition" in order to "erase" the physical drive.

Both of these methods will destroy all partitions and volumes including Filevault encrypted volumes.

Once in a long while Disk Utility can become confused if the drive or partition table isn't in its expected form in which case writing zeroes to the beginning of the drive to destroy the partition table will solve that problem and allow Disk Utility to properly erase the drive.

If you still have problems, then see if you can install Linux Mint onto the laptop (allow Linux Mint to use the whole drive). This will be an easy way to tell if you may have a failing SSD. Sometimes when SSDs fail they are supposed to go into a read-only mode.

I can provide instructions for creating a bootable Linux USB drive in order to check the health of the SSD. Plus there is a way to perform a hardware reset on the SSD to erase it and reset it to factory defaults and potentially fixing any SSD issue.

davidrfrench wrote:

I have a MBP with SSD which won't boot. (I can enter the Filevault password but the progress bar gets to 100% and then stalls. If I boot into Single User mode I can't run fsck without it throwing up an endless loop of errors to do with spaceman_freed. The same booting in Verbose mode.)

If I try to use Disk Utility from Recovery mode or a USB boot drive, anything I try to do with the APFS drive hangs Disk Utility, so I'm working from the Terminal in Recovery mode.

At this point all I want to do is wipe the drive so I can install Mojave from scratch. However I can't wipe the APFS-formatted drive - each method I try I get a different setback. When I tried just running the Mojave install from a USB drive, it got to the point of prompting me for a password for the drive (it takes several minutes for the prompt to come up from the point I click Unlock...) and then just seems to hang, as if it's unable to decrypt the drive.

There's an APFS container (disk2) with four volumes (disk2s1 to disk2s4). disk2s1 is FileVault encrypted.

I tried decrypting the volume (diskutil apfs decryptVolume /dev/disk2s1 -user UUID); it accepts the password and says it's decrypting in the background but won't return me to the command line. Nothing seems to happen for several hours. I can ctrl-c out of this but the disk remains encrypted.

I then tried deleting the Container (diskutil apfs deleteContainer /dev/disk2); this failed at the point at which it tried to unmount the volumes. Error -69888.

I then tried deleting the volumes individually (diskutil apfs deleteVolume /dev/disk2s1); after five minutes or so I got "Error: -69888: Couldn't unmount disk". This happened on the encrypted or unencrypted volumes.

Eventually after several reboots diskutil unmountDisk force /dev/disk2s1 worked to the point that the deleteVolume would get as far as "Deleting Volume" with an ASCII progress bar getting to 50%; however after many minutes with no progress, the machine hangs with a black screen and has to be force-restarted. I note that during this process the fan is kicking in, which seems odd given I wouldn't think deleting a volume should be too computationally intensive.

I've also tried doing all this from Terminal from a USB drive set up as a Mojave installation disk, to the same effect.

Please can somebody tell me how to wipe this drive! I'm starting to think it's a hardware fault with the SSD.

You do not say what exact Mac this is...

Verify you are trying to erase, reformat, initialize the parent drive

DiskUtility>View>Show All Devices

If you have a T2 chip you may have to boot to Recovery

About Startup Security Utility - Apple Support https://support.apple.com/en-us/HT208198

What is the Startup Security Utility on Mac? - Apple Support https://support.apple.com/lt-lt/guide/mac-help/mchlf5346320/mac

About Secure Boot - Apple Support https://support.apple.com/en-us/HT208330

davidrfrench wrote:

MacBook Pro 13-Inch "Core i5" 2.6 Mid-2014

I'm in Recovery mode already...Regardless of whether I try to erase the media, container or volume, it still hangs Disk Utility :(

And in all this mess did you try resetting the  SMC  https://support.apple.com/en-us/HT201295 for a normal boot process.

If you have a boot clone as a backup, try using that cloning software (ex Carbon Copy Cloner) to erase and clone back to the internal drive.

You can try and verify the health of the hard drive by running DriveDX.  However with an external drive you will need to use a special USB driver so DriveDX can communicate .

Apple can attempt to recover data from the laptop and/or reinstall a macOS using a bench tool which connects to the Logic Board to access the SSD —unless of course the SSD itself has completely failed.

Apple does not recover data from laptop as far as I know.

Always make a backup. Data is never under warranty. Data is the customer's responsibility.

Data recovery by third party can get quite costly.

If the disk is accessible somehow, maybe Apple can help.

You're welcome. Glad you are back up and running again.