Using New Outlook on Windows for professional communication and productivity
I understand how concerning it can be when emails suddenly disappear from your inbox.
To help narrow down the issue, could you please confirm whether the missing emails are only missing from the Focused tab or whether they are also missing from the Other tab?
In the meantime, you can try the following steps in New Outlook for Windows:
1.Search for missing emails
Use the search bar to search for a missing email by sender, subject, or keyword. If available, set the search scope to all folders to check whether the messages were moved elsewhere.
2.Check other folders and inbox rules
Check the Archive folder and any custom folders in your mailbox. Also, go to Settings > Mail > Rules to see whether any rules might be moving or deleting messages automatically.
3.Check Outlook on the web (assuming this is Exchange/Microsoft 365 account type)
Sign in to Outlook on the web using the same account and check whether the missing emails appear there. This can help determine whether the issue is specific to New Outlook or also affects the mailbox online.
4.Contact Your IT Administrator
If you're using a Microsoft 365 work or school account with Exchange Online and the missing emails are no longer in Deleted Items, please contact your IT administrator and ask them to check whether the messages may still be available and recoverable.
Your IT admin can refer to the following Microsoft documentation for guidance: Find content in mailboxes using eDiscovery
Please let me know if you have any updates after trying these steps.