Browsing the All Unreads view on desktop lets you catch up on the messages you missed when you were away from Slack. While you're at it, you can act on those messages, too:
Scan what's new and mark channels as read
Add a reaction to a message, start a thread, or show message actions
Jump from the all unreads view to a channel to post a new message
Keep in mind: For now, all unreads is only available on desktop. Stay tuned for updates! 📰
Set your All Unreads view
From your desktop, click your workspace name in the top left.
Select Preferences from the menu.
Check or uncheck the box next to Show All Unreads.
Note: Messages in muted or archived channels aren't included in the all unreads view.
Navigate unread messages
Sort unread channels
Decide how to prioritize your unread messages by changing how they’re sorted. You can sort messages alphabetically, by newest activity, or by oldest activity. On paid plans, you also sort scientifically — a view tailored to how you use Slack.
Mark messages as read
Click Mark as Read to clear that channel's messages when you've finished reading them. You can also scroll to the bottom of the all unreads view and click Mark All Messages Read.
If you clicked Mark as Read too quickly, just click Undo to keep those messages in your all unreads view.
Save a channel's messages for later by clicking the arrow icon beside the channel name to collapse it. Click the arrow again when you're ready to read the unread messages.
Refresh for new messages
When new messages become available while in the all unread view, the syncing arrows icon will appear in the header. Click the icon to reveal a fresh batch of unread messages!