Many passwords in Keychain missing after local migration from MBP 2013 (Big Sur) to MBP 2021 (Monterey)

rademac wrote:

Both Mail and Safari ask me to put in all newer passwords as if they are not stored anymore. When I open Keychain, all newer passwords are missing. The older passwords available were used ago to the time before my older MBP 2013. I want to be sure all passwords are transferred to be able to give up the MBP 2013 and therefore I want to know the correct procedure to migrate all Keychain passwords.

What I did in detail:

I use local passwords using Keychain without iCloud (both machines). I migrated all kinds of user data from the old MBP 2013 (Big Sur) to the new MBP 2021 (Monterey) directly using the Migration Assistent (and other data as well).

In ~/LibraryKeychains (without slash in the middle) all files seem to be the same (judged by names & file sizes).

Also in ~/Library/Keychains (with slash in the middle) the files are the same. The difference is: there has been a hashed directory on the old Mac which has been copied correctly, but there is another hashed directory on the new Mac.

I followed the advice of the Apple installation support and replaced the whole ~/LibraryKeychains directory by the contents of the same directory from the older Mac. No passwords appeared. The only difference is, that the original hash changed, seemingly to the other hash that had been there before. Still, no old passwords appeared.

The most trouble free way to move to a new machine, is using the Setup Assistant on the initial boot of a brand new machine— you have one shot here. Set up your MacBook Pro - Apple Support

The second best way is use the Migration Assistant.

How to move your content to a new Mac Move your content to a new Mac - Apple Support