Somehow a block of WiFi passwords ("AirPort network password") disappeared from my System.keychain file.
I'd prefer to not replace the whole keychain with a backup, as the most recent backup is a week old and I'm not sure what might have changed since then. Instead I'd like to copy just the WiFi passwords from the backup to the default System.keychain.
I've restored a recent System.keychain to another folder, and I can add it to Keychain Access, and I can see all 90-odd WiFi passwords that I want. I just can't open any of them or drag them into the System.keychain. When I try, I'm prompted for the "keychain password" which is not my login password.
I think the password to use may be found in
/var/db/SystemKey; however, I can't figure out how to use it. Thanks for insight!