When Outlook does not show new mail, the message may be hidden by a view, moved by a rule, filtered by the server, or stuck behind a sync problem. Check whether the email arrived somewhere else before assuming it was never delivered.
Does this affect you?
Use this for Outlook for Microsoft 365, Outlook 2021 or 2019, Outlook on the web, and common Exchange, Microsoft 365, IMAP, or POP accounts.
Check folders, filters, and rules
The email may already be in the mailbox.
- Open Junk Email and mark legitimate messages as Not Junk.
- Check Focused and Other tabs, and clear any message-list filter.
- Review File > Manage Rules & Alerts for rules that move, forward, or delete mail.
- Ask the sender to confirm the exact address they used.
- Search All Mailboxes or All Folders for the missing message.
Fix sync or delivery problems
Use this if the message is not visible anywhere in Outlook.
- Check Outlook on the web or provider webmail. If the message appears there, desktop Outlook has a sync issue.
- If webmail does not have it, ask the sender to check for a bounce-back.
- Use Send/Receive All Folders or F9 to force sync.
- Make sure Work Offline is not enabled.
- Check mailbox storage or quota.
- Run Outlook account Repair for Microsoft 365 or Exchange accounts.
More control
Check for suspicious forwarding rules
Unknown forwarding rules can be a sign of account compromise. Delete anything suspicious and change the account password immediately.
Subscribe IMAP folders
For IMAP accounts, confirm the Inbox and other needed folders are subscribed so Outlook syncs them.
Re-add mobile accounts
If mail appears on desktop but not phone, remove and re-add the account in Outlook mobile.
Check provider quarantine
Some providers block spam before Outlook can see it. Sign in to provider webmail and inspect spam or quarantine folders.
Sources
- Microsoft Support – Troubleshoot missing or lost email (2025)
- Microsoft Support – Fix problems with sending and receiving email (2025)
- Microsoft Support – Use rules to automatically forward messages (2024)