Sync issues with Outlook for Mac

Question

Hi, For the past few months, I've been experiencing an odd, odd issue. I'm using Mac OS Catalina with Outlook 16.65 (22091101).

Outlook sends and receives new email normally. However, read/unread status and moves/deletes are not synchronized back to O365. I could spend many hours working on my MacBook. I'm sending, receiving, moving, and deleting email without issue at that time. New mail is coming, and mail that I'm composing is being sent, but Outlook isn't informing me of any sync issues.

But then I'll check email from another device or my phone, and all of the mail that I've previously cleared out of my inbox on my MacBook remains unread and in my Inbox on every other device. Restarting Outlook on my MacBook doesn't help, but if I restart my MacBook and then restart Outlook, Outlook will eventually sync everything.

Answer 1

Dear Anna Zhang1,

Thank you for posting in Microsoft Community. We are happy to help you.

Based on your description, as you mentioned | I'm using Mac OS Catalina with Outlook 16.65 (22091101) |, initial stage could you please allow me to troubleshoot this scenario via below mentioned way?

* First, kindly try to update your MacOS version such as (Big Sur or Monterey) and check f it makes any difference.

* Also, kindly update latest Office version to check if gives any different result scenario. To check Office update history for Mac, here is official document: Update history for Office for Mac - Office release notes | Microsoft Learn

* On the other side, I need to double confirm are you using Legacy outlook or new Outlook experience on Mac?

I will look forward to your next update for further analysis. I am really appreciating your precious time and kind cooperation.

Have a good day.

Sincerely,
Darpan