Hi Love Givik ,
Welcome to Microsoft Q&A Forum!
Have a good day and I hope you're doing well!
Thank you for sharing the details. I completely understand how frustrating it can be when the Outbox keeps syncing and pulling old messages back from the server. This behavior usually relates to how Outlook synchronizes with the Exchange mailbox, especially after network interruptions or when using Work Offline mode.
To find the most accurate solution, I’d like to clarify a few points:
Confirm Your Exchange Environment
Are you using:
- Exchange Online (Microsoft 365)
- On‑premises Exchange Server in your own domain
- Hosted Exchange from another provider
If it’s on‑prem, do you know which Exchange version (2013/2016/2019, etc.)?
Cached Mode & Sync Details
- On the affected workstation, is the account configured with Cached Exchange Mode enabled?
- Have you already tried creating a new Outlook profile for this mailbox on that same machine? If yes, did the “39 messages on server” behavior persist or change?
I hope this helps us narrow down the issue. I look forward to your response so I can gather more insights and provide the most suitable troubleshooting steps. Thank you for your cooperation. I truly appreciate your effort on this!
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