macOS Sequoia. An error occurred preparing the update. Failed to personalize the software update. Please try again.

Hi, I'd just like to add a datapoint here. I'm on a MacBook Pro M1 Max attempting the update and I received both of these exact errors. I found that disabling Find My Mac was the recommended action as in this thread, however this didn't make a difference for me.

What did work was attempting the update again but from a fresh user account. If you understand what I mean by this then you don't need to read any further.

Anyone unsure by what I mean by that, here's a walkthrough.

So while leaving Find My Mac disabled, not sure if it's necessary but can't hurt as long as one remembers to re enable it after all is done:

• create a new empty Administrator account via System Settings > Users and Groups. As I was only going to have this account around for this task, I didn't add a password, but you can and maybe should especially if you don't plan to delete the account straight away afterr
• log out of your usual user account entirely
• log in with the new account, clicking through as minimally on the OOB setup screens as possible (not logging in to iCloud or anything like that)
• initiate the software update via System Settings > General > Software Update
• The update restarts once or twice and is done!
• Re-enable Find My Mac if you disabled it at any point for troubleshooting
• Remember to log out of the new account and back in with your original account and delete the new account (from Settings > Users and Groups) unless you've added a secure password and/or security is not a major concern. Some people may want to keep the clean user account around for troubleshooting purposes in the future so they don't have to go through the setup steps again in the event that it's necessary again.

Hope this is of help to anyone. Apple Silicon blessings to all