Suddenly cannot start-up/log in: "SDErrorDomain error 104"

Try running First Aid on the physical SSD and hidden Container. Within Disk Utility click "View" and select "Show All Devices" so that the physical drive and hidden Container appears on the left pane of Disk Utility. Run First Aid first on the physical SSD, then on the hidden Container. Even if the First Aid summary says everything is "Ok", click "Show Details" and scroll through the report to see if any errors are listed. If there are errors, then run First Aid again until they are gone. If after several scans the errors remain, then they cannot be fixed and you will need to perform a clean install of macOS by first erasing the disk (destroys all data on the drive) followed by installing macOS & restoring your data from a backup.

Ignore the Disk Images since they are just the macOS installer.

You can try booting into Safe Mode which will prevent the automatic launching of third party software during boot & login. If Safe Mode works, then it most likely means you have an issue with some third party software.

FYI, you are a bit behind on macOS updates.....I believe Monterey is up to 12.7.6.

If none of this works, then you may want to try a DFU Firmware Revive which resets the security enclave & system firmware.

CharPatton wrote:

I followed your instructions and ran First Aid on what I think was the physical SSD and all checked out AOK: [1] 

Appears correct.

I then tried it on what I think was the hidden container [2] 

And got this error [3]:

How do I “Mount the locked volumes”?

While the "Data" volume is selected on the left pane of Disk Utility, click the "Mount" button on the right pane of Disk Utility. Then you should be able to run First Aid on the Container.

I tried booting into Safe mode but nothing happens when I click ‘Continue in Safe Mode’ [4]:

Not sure, but it may mean you need to try performing a DFU Firmware Revive.

 How do I “first erasing the disk (destroys all data on the drive) followed by installing macOS”?

Here is an Apple article with details:

Use Disk Utility to erase a Mac with Apple silicon - Apple Support

Or if you have access to another Mac (most likely the other Mac will need to be running macOS 15.x Sequoia), then you could instead perform a DFU Firmware Restore which resets the security enclave, system firmware, internal SSD and pushes a clean OS onto the internal SSD (I'm not sure which version of macOS it will install).

FYI, I am on 14.7 Sonoma not Monterey.

Thanks for the correction. I guess I had a brain processing glitch.

I'm glad you were able to resolve the issue. At least you know your backups work for the most part. Unfortunately sometimes certain things may not be smooth when restoring a backup. I even had a few issues migrating from an one Mac to another Mac where I have only a very few number of third party apps installed for work. What surprised me was all my migration issues were due to Apple software & services while all the third party apps & settings transferred without any issues.

Thanks for following up. Its always nice to know how things end up.