Sending, receiving, and organizing email in Outlook.com
Sorry to hear about your situation, marc eastham.
I know how frustrating it is to lose such a large block of email, especially after you've checked carefully from all sources. Just wondering, have you tried any of the AI suggestions above, and what's the results? From my personal experience though, cases like this are something your should escalate rather than keep troubleshooting yourself.
That said, since Microsft Q&A is just a user-to-user support forum, contributors here cannot review your account or server-side status. Since you have already confirmed the emails are not deleted or archived, please contact:
- Sign in to https://outlook.live.com/ on a computer.
- Open the Help tab > click the (?) icon at the top > describe or select your issue.
- Try the suggested solutions. If they don't make any differences, click Contact support.
- Alternatively, start from Contact Us - Microsoft Support
- Enter / choose an issue > click Get Help to make a request
- Scroll down > click Ask our Support Assistant and follow guidance
- If the issue persists, specifically state in the chat box that you need direct help.
- The Contact Support button should appear > click it > select the chat in browser option.
Note: The support contact team only works at certain times, so if the last window shows that it's unavailable, try opening it again the next day. If you prefer phone support, you can leave a phone number. This way, they can call you and help you. If you don't see chat option, choose another category and ask to escalate.
I wish I could be a greater help in your situation, but this issue seems to be more serious than just some syncing error. This is just a community platform, contributors here don't have access to internal or backend diagnostics tools to resolve the matter.