Mail issue with MS exchange server on macOS Catalina

Well... for me this is solved finally.. How? By simply removing and then reinstalling the exchange account on Mac OS X, and configure it manually (after the Catalina update 10.15.3). Be careful though! Since your exchange account and Mac mail were disconnected for a while, folders will contain emails on your mac but not in the same folders in your exchange account. These mails will be in your main inbox folder. So if you use folders where you frequently delete/ move messages to and from, take a picture of those, and replace the messages in those folders after re establishing contact with the exchange server... You will find old messages in folders you thought were already long gone..

For me deleting/ moving/ reading messages in Mac OS X now nicely get updated at the exchange server again....

I was having some minor niggles with Apple Mail + Exchange (Office 365) but v10.5.2 seems to have resolved at least the perceivable ones.

Try setting it up in a alternate user account, just to test it. Setup a bogus Administrative user, and once logged in setup the Exchange account. If the issue is resolved, it's likely a compromised preference file or Envelope index.

Interestingly enough .. this problem was evident late last year as described by others. It suddenly starting working again and I never thought more about it. Until YESTERDAY .. the exact situation appeared.

I ended up using the memory bank .. I seem to recall that as a last ditch effort I completely deleted the MS Exchange account accessed through MacMail. I then shut down and restarted MacMail, and re-installed it with a new password as a total fresh start.

BINGO .. doesn't make any sense but it appears to be back functioning as it should.

At some point after installing MacOS Catalina I started having issues with my school's Exchange server: specifically my Apple Mail app wouldn't update its inbox with incoming messages. I found this thread but couldn't quite get an answer that would provide a stable solution. The following advice given to me by our tech support proved very helpful in my case:

• Open the System Prefs and select Internet Accounts
• Select the Exchange server, click on Details, delete the currently inserted password and then re-enter it

I know it sounds like voodoo but it solved my problem (4 days without a problem) so it might be worth to give it a try.

For me, (creating a new user on MacOS and logging in and using only that new user, starting from scratch with Apple Mail, creating all the needed accounts), has been working well for just a little over 4 weeks now. So, not long enough to know that this problem is fixed.

I do see other "issues" (BUGS!) in Mail that make me think of memory leaks and the like (a.k.a. BitRot). There is still the issue of displaying Exchange mail messages with the same subject only displaying the content of the first message in the sequence. Also, sometimes, when reading a Message in Apple Mail, while Outlook properly shows a message as having been read, the Apple Mail client does not change from Bold to non-Bold and does not clear the little circle so, in Apple Mail, it still looks like it is unread...

So, which was asked, as I read an email in Apple Mail, within a few seconds, the email entry in Outlook changes from unread to read.  When I delete a message or move it to another folder (on my system), the message disappears from the list on Outlook.  Outlook even properly reflects the flagging (though only represents a single colorless flag regardless of the message's flag color in Apple Mail).

The whole experience is still frustrating as ****. I'm told by Apple support that if something works with a new account, it is not an Apple problem so they wash their hands of any further troubleshooting. On that score, the "Console" program, where I'm ostensibly able to look at logs, is REALLY FRUSTRATING.

Ok. Anyways, things still seem stable with Apple Mail and exchange.

I have found that if I "delete" the MS Exchange Account in MacMail .. then re-install it the problem goes away.

Having said that you are correct it's JUST A TAD FRUSTRATING because you never know when it will happen and

before you are aware you have lost som vital attachment of some kind. I am seriously contemplating going away

from Mail and migrating to other option.

I had to rebuild my exhange mailbox with was a pain, it re-downloaded a lot of emails I moved over previously. It seems to be working now, moved messages and then checked to Office 365 to ensure they were moving out of the inbox. I hope there are not anymore issues, I love Apple Mail and do not want to have to move to Outlook.

I did see an error after rebuilding where it keeps "downloading messages." In another post I read to un-select "keep draft messages on server" and this has helped fix that error after I restarted mail.

I have an inconvenient "solution":

I delete the exchange account in apple mail and generate it new. This fixes the issue for a certain time, that it occurs again, but can be solved like this again.

Hopefully Apple generates with MS a solution for the issue.

We have had this issue with Apple mail and Office 365 for over a year. Sure, recreating from scratch works every time for a few months but if they have a large mailbox the download takes a lot of time. I have aggressively archived, changed the connection setting, drafts on server settings and reordered the mailbox into smaller chunks but once this start happening there is no fix. You can rebuild the main inbox, which I keep small on purpose, for a few weeks. However, then it just stops receiving email but you can send and it even syncs deletions correctly. I keep steering people to Outlook which, yes always works (it is not the Outlook 2010 everyone dislikes) for a reason, but I have a few people who love Applemail but the business interruption and support for it is tedious. Good thing they can fallback to Outlook when it stops working. Why doesn't Apple do anything for the Applemail lovers or at least admit there is a issue they can't resolve or wont resolve with Office 365. I am just spending another two days rebuilding a mailbox and not sure why I bothered posting no one from Apple is listening. Oh and yes, I tried safe mode, different email accounts and a brand new laptop build ( yes I bought a MacBook Pro 2016 for the new keyboard and to start fresh with the result being the same) many times.

Same here, although there were some issues before the upgrade (more in particular never-ending-calendar-popups) it's no longer workable with Catalina.

Question: are you using, or have installed, any type of VPN connection on your mac?

Reason for my question is that apple mail (together with other features in the OS, such as 'import (scan) from iphone' in folder, Finder in general, ...) has issues when the application keeps running while the tunnel goes on and off (even in split tunnel mode).

Test: you're unable to mark certain messages as 'read' (the blue dot stays where it is) but once the VPN goes on, all seems normal and the blue dot goes away marking the message as 'read' (correct state).

We're investigating all firewall rules and VPN settings to find potential anomalies. We're using 365 and Exchange hybrid mail environment.

Hello and welcome to Apple Support Communities kindenk,

I see that you're having an issue with mail since updating to macOS Catalina. I understand your concern, and I'd be happy to help.

Let's start by trying a couple steps to try to isolate this issue further. First, try starting your Mac in safe mode and then testing to see if the issue remains. If needed, the first link listed will guide you through starting up in safe mode. If the issue remains in safe mode, then the next step you can try is testing in another user account. The second link will guide you through those steps, if needed.

Use safe mode to isolate issues with your Mac

How to test an issue in another user account on your Mac

Let me know how this goes.

Have a great day!

@John P.

I tried this several times and I am talking about issues with MS Exchange server not about Exchange (Office 365).

A not efficient workaround is, to delete the exchange account on the MAC completely, then create it new. This works then for several days, than this workaround has to be repeated. With a large E-Mail-Database this takes quite a long time, and some E-Mail attachements are most of the times lost afterwards.

For me, this is not a VPN or firewall permissions issue. First, I do not (always) use a VPN. If I read an incoming Exchange message and it's status doesn't change to read (blue dot goes away), I simply quit email and immediately come back and it is gone. So, as nothing has changed but the Mail client now acts properly, they are not involved; the issue is in the client. Furthermore, this is an intermittent situation.

I also have had this issue.

It definitely only occurs with my exchange server and Apple-Mail.

Deleting the account and Add it again will help - for some hours, sometimes for some days.

I did the same things you did, Armando

• created a clean new account
• added my exchange-account
• added my Apple-Mail Account
• and migrated all mailboxes

Apple Support told me to test it with a new user. I am not amused. All these settings.