Emails Not Received: Switching Sending User in macOS
In macOS, you can use the command line to send emails using various methods, including the printf command and the sendmail utility. However, you might encounter issues where emails sent using one user account are not received in another user account. This article explains the possible causes and solutions to this problem.
Understanding the Issue
When you send an email using the command line in macOS, the email is typically sent from the default mail delivery agent, which is usually sendmail. By default, this email is delivered to the local mail spool directory (/var/spool/mail). However, the email is not actually sent until the mail transfer agent (MTA) is started, which is typically done by the launchd system daemon.
When you switch user accounts, the launchd daemon might not start the MTA for the new user account, causing emails sent from that account to not be received by other user accounts. This can lead to confusion and frustration, especially when trying to troubleshoot email delivery issues.
Solutions
There are a few ways to work around this issue:
1. Start the MTA manually
You can start the MTA manually for the user account you are sending emails from. This can be done by running the following command:
sudo launchctl load -w /System/Library/LaunchAgents/com.apple.postfix.plist
This command loads the Postfix MTA configuration, which is the default MTA used by macOS. Replace com.apple.postfix.plist with the correct launch agent name if you are using a different MTA.
2. Use a different MTA
Another solution is to use a different MTA that does not require the MTA to be started manually for each user account. One popular alternative is Postfix, which can be easily installed and configured on macOS.
3. Use a mail server
If you need to send a large number of emails or require advanced email features, it might be better to use a mail server instead of the command line. Popular mail servers for macOS include MailEnable and Zimbra Collaboration Suite. These mail servers can handle email delivery and management for multiple user accounts, making it easier to send and receive emails from different accounts.
In summary, when sending emails using the command line in macOS, you might encounter issues where emails sent from one user account are not received by other user accounts. This is typically caused by the MTA not being started for the new user account. To work around this issue, you can start the MTA manually, use a different MTA, or use a mail server.