Change X-Mailer for Mail.app by admin | Oct 26, 2010 | OSX, Security | 0 comments In Terminal: defaults write com.apple.mail UserHeaders '{"X-Mailer" = "CHANGE TO THIS"; }' Submit a CommentYour email address will not be published. Required fields are marked *Comment * Name * Email * Save my name, email, and website in this browser for the next time I comment. CAPTCHA Code *