M1 MacBook Pro SSD full - cannot boot

tripletwenty wrote:

2021 MBP M1 2TB SSD disc critically full. On restart hangs after sign in screen. Will boot in Restore mode and can share disc with Mac Studio, but unable to move, copy or erase files from the MBP. I have used disc utility to repair disc volumes but still cannot get any space on disc to allow boot after restart. Cannot reinstall OS (not enough space). Any thoughts on what to try next?

You can try booting to SafeBoot mode—certain system caches get cleared and rebuilt, third party system modifications and system accelerations are disabled temporarily—often this is enough to get you logged in...

ref:  Start up your Mac in safe mode - Apple Support

SSD like to have 15-20% free storage at all times.

empty the trash is often over looked

do some general house cleaning, or move off large data if necessary...

If an APFS volume completely runs out of Free storage space, then it becomes impossible to delete files due to how the APFS file system works. Unfortunately Apple has not seen fit to reserve a small portion of storage to prevent this from occurring. Ignore the "Available" storage value since it is very misleading. Unfortunately the Free storage space value is only listed in Disk Utility and the Apple System Profiler while the misleading "Available" value is shown everywhere in macOS.

You can try checking if there are any APFS snapshots on the drive and try deleting one or more of them. Keep in mind these APFS snapshots are typically from backups of your computer.

Here is an Apple article with instructions for viewing & deleting APFS snapshots:

View APFS snapshots in Disk Utility on Mac - Apple Support

Otherwise you will need to erase the disk (aka delete the "Volume Group") in order to perform a clean install of macOS followed by restoring your data from a backup.

If you don't have a backup, then you can try putting this Mac into Target Disk Mode in order to attempt copying your files from the system. If the volume won't mount, then you will need to try using the command line to mount the volume in read-only mode. Or if you are familiar with the command line, then you can try transferring the data to external media while booted into Recovery Mode.....again, you may need to manually mount the volume in read-only mode if it is not mounted automatically.

I hope you have good backups since you may need them. There are a lot more new ways to permanently lose access to the data stored on the internal SSD of the recent Macs due to all the hardware, software, and security changes.