You can delete messages that you don’t need anymore to help keep your mailboxes manageable, and to free up storage space on your Mac or on the mail server. Options in Mail preferences determine whether you can view and retrieve messages after you delete them.
Delete a message
To delete a message from a Mail notification or with a swipe, the “Move discarded messages” option in Viewing preferences in Mail must be set to Trash; otherwise, the message is archived.
In a Mail notification: Move the pointer over the notification, then click Trash.
In the Message viewer: Do one of the following:
Swipe left with two fingers, then click Trash, or swipe all the way to the left until the message disappears.
Move the pointer over the message header, then click the Delete button that appears.
Select a message in the list, then click the Delete button in the Mail toolbar.
Tip: To prevent the next message in the list from being automatically selected (and marked as read), press and hold the Option key when you delete a message.
Delete multiple messages
In the message list, select one or more messages or conversations, then click the Delete button in the Mail toolbar or press the Delete key. If you select a conversation, all of the messages in the conversation are deleted.
Search for a set of messages to delete. For example, search for messages dated August 1 through September 5, 2017 by entering “date:8/01/17-9/05/17” in the Mail search field. Or, search for messages from a specific person by entering a name in the search field. Then select and delete the found messages.
Delete a mailbox, which deletes all the messages it contains.
View deleted messages
The way you view deleted messages depends on how you set options in Mail preferences. To check yours, choose Mail > Preferences, click Accounts, select an account, then click Mailbox Behaviors.
If Trash Mailbox specifies a mailbox on the mail server or on your Mac: You can view the messages in the Trash mailbox until they’re permanently erased. To retrieve a deleted message before it’s erased, drag it from the Trash mailbox to another mailbox.
If Trash Mailbox specifies None: The messages may temporarily remain in their original location, but are dimmed or hidden. To show or hide them, if available, choose View > Show Deleted Messages or View > Hide Deleted Messages.
Permanently erase deleted messages
Automatically erase messages: Choose Mail > Preferences, click Accounts, then select an account. Click Mailbox Behaviors, then in the Trash section choose when you want Mail to permanently erase deleted messages—for example, after one month.
If you have an IMAP account whose server is set up to delete older messages, they are erased regardless of your settings.
Manually erase messages at any time: Choose Mailbox > Erase Deleted Items, then choose an account.
If you mistakenly delete messages, you can drag them out of the Trash mailbox to another mailbox. Or select them in the Trash mailbox, then choose Message > Move to > [mailbox].