MacOS Mail Status Doesn't Sync with Exchange

Hi!

Here to help!

There's a couple of things I am thinking of.

First, Push vs Fetch (notify) - it's about alerts, but still) - it may be that when you make a change on the Mac in the email, that it is not directly pushed to other devices via the ESP (email service provider).

Another thing may be, the connection -or interference- on the Mac.

I would like to try and see what happens in a fresh user account. Create a test user ( > system settings > users and groups) > you don't have to log in with aple ID, just run through the set-up, open mail.app and add the exchange account (correct SMTP / IMAP etc). Test sync. So we can rule out VPN, Antivirus, Clean my mac etc).

If issue remains, delete test user (including homefolder) and try on a different, known-good network.

If issue still remains, consider removing the exchange account from mail.app > preferences or accounts and re-add it.

If still remains - consider changing password (this will generate [force]a fresh, new "handshake" with all servers").

Let me know if this helps!

Kind regards

RRD