Why: com.apple.xpc.launchd(1) com.openssh.sshd: Service exited with abnormal code: 255
If you recently enabled SSH on your Mac, you may start to see messages in your Console system.log file similar to below.
com.apple.xpc.launchd[1] (com.openssh.sshd.xxxxx-xxxx-xxxx-xxxx[]): Service exited with abnormal code: 255
There are few reasons for receiving this message as mentioned online.
- In your sshd_config, you changed PassworAuthentication to no. A docuemtned fix states changing this to yes (and uncommenting the line) fixes the error, but this is not true. It also is a pointless change if your forcing no password authentication to begin with.
- The Mac OS X firewall is enabled and not allowing the Remote Login (SSH) service. If you are allowing the service, you may still receive the error messages.
Even if you are receiving the sshd error messages in your Console, you are still able to SSH to your Mac. In this case, the errors are irrelevant and back-filling your log file.
If you have a solution for this, please use the comment form below to let us know.