AFP can be persnickety about you doing something as painfully silly as authenticating into a host using a password sent in cleartext (completely unencrypted). But when you’re troubleshooting it can be useful to disable this behavior, if only to test and then re-enable again. To do so: defaults write com.Apple.AppleShareClient afp_cleartext_allow -bool YES And to disable the warning: defaults write com.Apple.AppleShareClient afp_cleartext_warn -bool NO