Outlook will allow you to keep track of your mail messages that share the same subject and keep them all together. This function is called Conversations, commonly known as email threads. This document will teach you how to manage your Conversations.

View Messages by Conversation

• When you arrange messages by conversation, messages in a folder that share the same subject appear together in the message list. The messages within each conversation are sorted with the newest message on top. When a new message is received, the entire conversation moves to the top of your message list.
• Collapsed conversations appear with right-facing arrows and expanded conversations appear with a down-facing arrow. Select the arrows to expand or collapse conversations.

Turn Off Conversation View

• On the Organize tab, select Conversations to deactivate.
• If you want to turn Conversations back on, just select Conversations under the Organize tab again.

Other Commands

Notes

• To set preferences for how conversations are displayed in the message list, on the Outlook menu, select Preferences, then under Email, select Reading. Under Conversations, select the preferences that you want.
• Messages in the Junk Email and Deleted Items folders are not included in conversations.

For more information see Microsoft's View email messages by conversation in Outlook 2016 for Mac.