List Preview

The number of lines of the message to show in the message list.

Move discarded messages into

Choose whether to delete a message or move it to the Archive mailbox when you swipe left on a message in the message list.

This setting also determines whether you can delete or archive messages from Mail notifications.

Show message headers

Show default or custom fields in message headers.

To add fields, click the pop-up menu, choose Custom, click the Add button , then enter the name of a message header, such as Return-Path.

Display unread messages with bold font

In column layout, show unread messages in bold to help distinguish them from messages you have read.

Load remote content in messages

When remote content is retrieved from a server, information about your Mac can be revealed. You can deselect the option for increased security, but some messages may not display correctly.

Remote content isn’t displayed in messages that Mail marks as junk.

Use Smart Addresses

Show recipients’ names but not their email addresses (if a recipient is in the Contacts app or the Previous Recipients list, or on a network server).

Use dark backgrounds for messages

Show messages in the preview area and new messages you’re writing with a dark background (when this option is selected) or a light background (when this option isn’t selected). This option is available only if you selected the Dark appearance in General System Preferences.

When this option is selected, you can switch to a light background while viewing or writing a message. Choose View > Message > Show with Light Background. To see the message with a dark background again, choose View > Message > Show with Dark Background.

Highlight messages with color when not grouped

When conversations are turned off, highlight the messages in a conversation in the message list, to help identify them more easily. Click the color well to choose a highlight color.

Include related messages

Include related messages (those located in other mailboxes) when viewing a conversation.

Mark all messages as read when opening a conversation

Mark all unread messages in a conversation as read when you view the primary message of the conversation.

Show most recent message at the top

Display the most recent message in a conversation first in the preview area. If deselected, the oldest message appears first.