Postifx error message Can't send mail: sendmail process failed with error code 75

Last Update: 12.12.2008

Today I ran a rsync backup script which afterwards sends a logfile of the backuped files to an e-mail address. At the end of the script, I received an error message that the message could not be sent. Here's the error message:

postdrop: warning: uid=0: Illegal seek send-mail: fatal: root(0): queue file write error Can't send mail: sendmail process failed with error code 75 postdrop: warning: uid=0: Illegal seek send-mail: fatal: root(0): queue file write error Can't send mail: sendmail process failed with error code 75

At the begin I thought I misconfigured postfix to send local e-mails so I did a little research on Google. It seems to be a problem with the filesize. In your postfix main.cf you can set the value of the maximum size of an e-mail. Because this was the first time I ran this backup script on this server, the logfile was obviously huge. The second time I ran the script, the filesize was of course (rsync) smaller and the mail with the log could be sent.

So the fix for this error message is to increase the value "message_size_limit" in your main.cf unless you received this error message because of a special occasion like in my case.