Using New Outlook on Windows for professional communication and productivity
In new Outlook for Windows, Send/Receive has been replaced by Sync. Pressing F9 or going to View > Sync forces a manual sync, so the current behavior confirms mail can arrive when sync is triggered.
Try these checks and fixes:
- Force a manual sync once and watch for the status message
- Go to Mail > View > Sync or press F9.
- A status message should appear at the bottom of the message list while Outlook is syncing.
- Check whether this is a sync issue in new Outlook
- If mail appears only after Sync, the issue is likely with background syncing rather than the mailbox itself.
- Note: third-party accounts such as Gmail, Yahoo, iCloud, or generic POP/IMAP do not have the same manual Sync capability from the button.
- If messages are delayed or stuck, check for a large message in Outbox
- Open Outbox.
- Start with the oldest stuck message.
- If it has an attachment larger than 20 MB, remove the attachment and resend with a smaller file or a link instead.
- A large stuck message can block sending and later messages.
- Compare with Outlook on the web
- If new mail appears immediately there but not in new Outlook until F9/Sync, the problem is isolated to the Outlook client.
- Remove and re-add the account in new Outlook
- Go to Settings > Accounts.
- Remove the affected account.
- Add it back, then test whether mail refreshes automatically.
- If the issue continues, create a new Outlook profile
- This is a recommended next step for Outlook refresh/sync problems that persist after account re-add.
If the mailbox is a shared mailbox, there is also a known issue where it may not automatically refresh for new email in Outlook.
- Sync to manually check for new mail and to send messages in Outlook
- I can't send or receive messages in Outlook
- How to get New Outlook to sync often - Microsoft Q&A
- Exchange Online shared mailbox not syncing new emails in Outlook desktop - Microsoft Q&A
- Shared mailbox is not automatically refreshing for new email in Outlook