10.6.2 Mail Server draws a blank, subject?

So we upgraded from 10.5.8 Mail server to 10.6.2 and everything went very smoothly. Mailstores were migrated and the transition from Cyrus to Dovecot was great. However once all the email was moved over and all the settings were double, and triple checked. People started complaining that every once in a while their email was not getting through the server, it was getting bounced back to the sender. At first I thought that it was an internal issue with the users on our network, then I got a complaint from someone from outside the organization trying to send an email to one of our users.

Great, another strange Apple bug I thought until someone was able to forward me the bounced email to my personal email account. Further insight in the error showed that the message was getting bounced back due to a blank subject line. As you can see from the example below its due to a blank or empty subject heading. Yes, apparently Apple has added this as an actual “Feature”. You can turn this off however by commenting out the only line of code in the file /etc/postfix/custom_header_checks.

This is the mail system at host mail.xxxxxxx.org.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<[email protected]>: host
mail.domain.org https://xx.xxx.xxx.xxx said: 550 5.7.1 empty subject

Turn off the mail service before you do this. Once the mail service is off edit the file using sudo pico.

/^subject: *$/ REJECT empty subject header in /etc/


#/^subject: *$/ REJECT empty subject header in /etc/

Start mail back up again and you will notice that the blank subject line blues are gone away.

Are You Getting Quality Mac Support From Your PC MSP?

We have assisted many businesses in implementing MDMs, developing custom security policies and procedures, and redesigning their networks.The list goes on and on. Contact us today and see how we can help you too.

Contact Sales

Drop us a line.

We are a remote and fully distributed, Nationwide Apple focused MSP serving Washington DC, Philadelphia, New York, Chicago, San Francisco, San Diego & more.

We focus on providing top notch Mac Support for small to mid-sized businesses. Contact us, and learn how we can help your company.

Full Name
Your email address
Phone Number
Company Name
How many Mac's & PC's do you have?
How many employees do you have?
Where are you located?
What challenges are you facing?

© Grove Technologies is a registered service mark trademark of Grove Technologies. Privacy Policy | Terms of Service. Cookie Preferences