Sendmail Error on OS X Mountain Lion I get an error when trying to run sendmail. I am on OS X 10.8 Mountain Lion.

sendmail: fatal: chdir /Library/Server/Mail/Data/spool: No such file or directory
Just execute in terminal

sudo mkdir -p /Library/Server/Mail/Data/spool
sudo /usr/sbin/postfix set-permissions
sudo /usr/sbin/postfix start


That did the trick for me.