Using classic Outlook for Windows in business environments
In this context, you can try two options below to see if it can help you:
1) Show the All / Unread toggle above the email list
- Open Outlook and go to your Inbox (or any mail folder).
- Look at the top of the message list, just above the column headings.
- Select Unread to show only unread messages, or select All to show everything (read + unread).
If you don’t see “All / Unread” there: in some builds those options appear under the All drop-down (and you can choose Unread from that menu), or you can use Filter Email on the ribbon.
Link instruction: View only unread messages in Outlook
2) Control how messages become Read when using the Reading Pane
On the View tab, under Layout, select Reading Pane > Options.
To automatically mark messages as read after previewing, enable Mark items as read when viewed in the Reading Pane and set Wait seconds.
To prevent auto-marking as read, clear Mark items as read when viewed in the Reading Pane.
Note: You can always manually toggle a message’s state by right‑selecting it and choosing Mark as Read / Mark as Unread or using Ctrl+Q (read) / Ctrl+U (unread).
Link instruction: Use and configure the Reading Pane to preview messages in Outlook
Hope my answer will help you
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.