Just checked my mail logs. Do any of these help anyone?
kwright:~$ tail /var/log/mail.log
Jan 2 21:23:31 grace postfix/postdrop[58322]: warning:
mail_queue_enter: create file maildrop/914822.58322: Permission denied
Jan 2 21:23:31 grace postfix/postdrop[55910]: warning:
mail_queue_enter: create file maildrop/947257.55910: Permission denied
Jan 2 21:23:31 grace postfix/postdrop[57538]: warning:
mail_queue_enter: create file maildrop/948799.57538: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[56649]: warning:
mail_queue_enter: create file maildrop/20845.56649: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[59072]: warning:
mail_queue_enter: create file maildrop/56169.59072: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[55272]: warning:
mail_queue_enter: create file maildrop/82728.55272: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[59839]: warning:
mail_queue_enter: create file maildrop/85157.59839: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[58386]: warning:
mail_queue_enter: create file maildrop/87065.58386: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[55946]: warning:
mail_queue_enter: create file maildrop/104351.55946: Permission denied
Jan 2 21:23:32 grace postfix/postdrop[57591]: warning:
mail_queue_enter: create file maildrop/125843.57591: Permission denied
kwright:~$ tail /var/log/mail.err
Jan 2 21:15:34 grace master[79805]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:16:35 grace master[79862]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:17:36 grace master[79904]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:18:37 grace master[79965]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:19:38 grace master[80002]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:20:39 grace master[80614]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:21:09 grace postfix/postqueue[80723]: fatal: Queue report
unavailable - mail system is down
Jan 2 21:23:04 grace master[81109]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:24:05 grace master[81158]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
Jan 2 21:25:06 grace master[81754]: fatal: master_spawn: exec
/usr/lib/postfix/sbin/0: No such file or directory
