Tahoe 26.4 broke the copying of login keychains. Apple has at last explained how you can copy them successfully, and what backup software needs to do. Explained in full.
Keychain Access
Login keychain behaviour changed in Tahoe 26.4, and now ties access to one Mac. That could cause problems, as the most reliable transfer is by two-Mac migration.
In Tahoe and later, using Macs with Secure Enclaves, copying the login keychain between them won’t work. But migration should be successful, and can also be used to create new VMs, such as Golden Gate.
From their origin with an email engine in 1993, to the addition of the more secure Data Protection keychain supporting passkeys and much more.
Which passwords, passkeys, wi-fi passwords, and so on are supported by Sequoia’s new Passwords app? Where has Keychain Access gone, and do you still need it?
Differences between file-based keychains including the login keychain, and Data Protection keychain. How the Passwords app in Sequoia caters for the latter.
iCloud Keychain is apparently the way ahead, but even Apple has a great deal more work to do before that’s feasible. A look at what’s needed.
Multiple requests for a keychain password, login password mismatch, broken keychains, expired certificates, and using the Data Protection keychain.
macOS has two types of keychain, and its tools for working with them, Keychain Access and the command tool security, only work fully with one type.
Solving repeated requests for passwords, telling the genuine from the bogus, how passwords can become mismatched, and more.
