Fix SSH problems after upgrading to macOS Sierra

After you’ve upgraded your system…

1) add following lines to the “Host *” block of ~/.ssh/config

Host *
    UseKeychain yes
    AddKeysToAgent yes

Just add the snippet at the very beginning of ~/.ssh/config file if there is no existingHost * configuration block.

2) Then execute the following commands

ssh-add -K ~/.ssh/id_rsa

ssh-add -A

3) Now everything should work like before upgrading to macOS Sierra v10.12.2 and up

Further information

OFFICIAL APPLE: Technical Note TN2449: OpenSSH updates in macOS 10.12.2

SSH-agent does not automatically load passphrases on the OSX Sierra keychain during startup

macOS 10.12.2 Sierra: Änderungen bei SSH Keys und Passphrase

macOS Sierra doesn't seem to remember SSH keys between reboots

Further questions?