Migration Assistant on M1/Monterey breaks Keychain


By now, it’s been well-documented that you can’t migrate your local Keychains in full, without some workarounds. Especially not the “Local Items” keychain. From the horse’s mouth:
“You can’t copy passwords stored in your Local Items or iCloud Keychain.”

Apple wants you to use iCloud to store your (keychain) logins, which you may disagree with…

The procedure to migrate your keychain data (and specifically Local Items) is listed in the Apple article, and with slight variations, around here as well… however this post is not about this.

I’m cloning systems where I don’t have specific important passwords stored. But of course, Keychain needs to work smoothly, or else the OS installation becomes a disaster of endless prompts. After running the Setup Assistant’s Migration Assistant, the Local Items keychain becomes impossible to access. It asks for the system’s admin password, but the correct one wouldn’t work. (Tried it 20 ways to heaven.) Trying to create an item in the keychain brings up this awesome error:

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An error has occurred: no error. I love it! Beats Word 2.0’s “out of memory” not-out-of-memory error messages.

Better yet, it’s equally impossible to access the Passwords panel in System Preferences, nor reset Keychain (in Keychain Access > Preferences). They also ask for the admin’s password and reject it.

macOS 12.6. This is reproducible.