How to Group Messages by Thread in Mac Mail
An email discussion that spreads across dozens of messages in your inbox is confusing to follow. The Apple Mail application in macOS and OS X prevents this by grouping emails in conversations (threads) instead of showing each email separately. You can turn off conversations or turn them back on easily for your Inbox or any other folder in Mail. To read your messages organized by a thread in any folder:
How to Work With Conversations in Mail
Only the newest message in a conversation shows in your email list by default—unless you request the oldest message in the drop-down menu above the list of emails or in Mail preferences.
To expand a single conversation and view all the emails in it, click the message as you would any other. When you expand a conversation, all the emails are visible in the reading pane.To expand all conversations rather than a single one, click View > Expand All Conversations in the Mail menu bar. When you don’t want to see them any longer, click View > Collapse All Conversations.Press Option+Up Arrow or Option+Down Arrow to move through the emails in a conversation quickly.
Preference Settings for Mail Conversation View
To pick conversation view settings that work for you in Mail:
How to Disable Grouping by Thread in macOS Mail and OS X Mail
To turn off conversation grouping in macOS Mail:
Emails from other folders, such as Sent, are not listed in the message list but appear in the reading pane’s full thread view.You can still reply to, move, or delete these messages.Related messages list the folder in which they are located.
How to Group Messages by Thread in Early Versions of Mail
The process of grouping messages by thread is slightly different in versions of Mac OS X Mail 1 through 4. To browse your mail organized by thread: If you want to turn off this feature, return to View on the menu bar and click Organize by Thread to uncheck the option.
