"failed to personalize the software update" macOS Sonoma on MacBook Air m1. Help

The issue is most likely due to the new concept of "Ownership" associated with the M-series Macs. Something goes wrong between the admin user account and the security enclave chip. It seems that sometimes migrating from an older system or Time Machine backup can introduce this problem, but there may be other things involved as well.

First, make sure you have a good backup now while you can still access the data on your internal SSD. I certainly hope you have already been performing frequent & regular backups since there are so many new ways to permanently lose access to the data on the internal SSD of the USB-C Macs due to all of the hardware, software, and security changes.

Some things you can try to do:

• Try creating a new admin user account and using that new macOS admin user account to update/install the software (this is not a real fix, but a temporary fix since your system still has an issue)
• Try a DFU firmware Revive which resets the security enclave & system firmware
• Try reinstalling macOS over top of itself (should not affect your data, apps, or settings)
• Perform a clean install of macOS by first erasing the disk (aka deleting the "Volume Group") followed by reinstalling macOS & restoring from a backup. Better yet would be to perform a DFU firmware Restore which resets the security enclave & system firmware & destroying all data on the internal SSD as well as pushing a clean OS onto the internal SSD.

The first option is just a temporary fix so you can update/install software. The 2nd & 3rd options probably won't work, but they are the least disruptive to try. The last option will most likely be the one which will fix things. If the last option still has the personalization issue, then try the last option again, but this time do not migrate or restore from a backup since that has been implicated in causing this problem. You will then need to manually transfer your data from the backup.

Here is another thread where I responded a few times and another user confirmed a clean install & manual transfer of data resolved the issue:

Failed To Personalise the software update… - Apple Community

Try this.

Start up your Mac in safe mode - Apple Support

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