Mac Mail not Syncing with Exchange email server on MacOS devices

I'm having same problem with Mail Big Sur 14. It will work for a while, then stop pulling new messages from my work exchange email, then it will work again, then stop again.

I always get mail on my iPhone using iOS mail. I've tried some of the suggestions and they don't permanently solve.

If Apple doesn't fix will have to use Outlook on my Macbook.

I have the same issue, and all of the proposed solutions (like powering down iOS devices) either do not correct this or do so temporarily. This is an intermittent problem, which makes it so difficult to diagnosis by this type of trial and error approach. Sometimes a solution seems to work and it is likely just a coincidence. Apple really needs to work on this; there are multiple threads on this issue so it is a major problem with functionality of Mail.

Your post made me think of something. I had over 50k emails in my work email inbox. Occurred to me that's a lot to sync on a regular basis and it takes up 10 gigs of hard disk space. Except for most recent emails I moved all 50k to the "archive" folder. Anxious to see if that fixes my problem.

I did same. This time I noticed the bottom of the left sidebar had progress info saying downloading x out of xxx messages. I've only used webmail client for years so I didn't realize it takes time to download 18 gigs of mail and attachments.

I think when I first setup I was expecting mail to come in with no delay, but system was busy synching mail folders.

There is another factor that you may or may not be factoring in -- the synch process does not just depend on the devices, it also depends on the Exchange server. The Exchange server may be getting behind the scenes updated software, patches, etc. that you might not be aware of. That can disrupt the process. Sometimes software updates are performed on the Exchange server and it takes multiple steps or tries by the server people to resolve new issues that are introduced. It's hard to see how downloading mail on an iPhone would stop the Mac from downloading unless there is an issue on the server side, which might have been resolved during the time that you and others were noticing these changes. We use MS-Exchange at work and I am on the distribution for the IT Group and what is happening on the server side. There are issues from time to time, they are constantly making server updates and security updates. I specifically recall instances where the iPhones were able to download email but the Macs and/or PCs were not updating, sometimes lasting for many hours.

Hi everyone,

I'm having the same issue with Big Sur after updating to 14.1

Tried all the advice on the forum, but no use. I'm now on using outlook which I hate with a passion.

Anyone manage to find a fix yet?

Thanks

Mark

Have the same problem. None of the suggestions work permanently. Deleting Mail's saved application state worked for a while a couple of times on Mojave. Not on Big Sur. Using Office 365, and Outlook for Mac (which I despise) works fine. Web Outlook (which I despise even more) works fine. Mail app on iPhone works fine. iCloud account mail works fine. The only thing that is unreliable is an exchange account in Mail on Mac OS. This is not a new problem. For me, it has been going on for years, dating back to when I had my own Exchange server. Office 365 is no better. I have over 350k messages in archives mostly on my mac and some in the cloud on office 365. Deleting and reinstalling my Exchange account takes about 3 days to synch and only temporarily solves the problem. It is incredibly frustrating. You can search the forums here and find issues dating back to Catalina. Work arounds are inconsistent such that they seem to work only by coincidence. Somebody once told me that Apple pays Microsoft licensing fees for using Exchange on iOS, but does not pay the fees on Mac OS. If that truly is what is going on, it is ridiculously hypocritical, petty, and insulting. If it is not the cause, then something else out of user control has to be the problem. I really, really wish Apple would resolve this. Maybe Apple could have the developers for the iOS Mail app give a seminar or two to the Mac OS Mail developers.

Thanks for your quick reply. Out of the items in your list, the only thing I have not done is delete the Exchange folders. Maybe that will be the secret sauce this time. Definitely will give your checklist a try and will let you know the results in a few days.

While I agree that a large quantity of messages in the in-box seems to be part of the issue, since I upgraded to Big Sur I have consistently spent time every night clearing out my in-box. When it lost connection at 4:55 am this morning, I had 24 unread messages and 7 read messages in my in-box. Coincidentally, at 4:55 am I had the exact same number of messages in the InBox in Outlook for Mac and the iOS Mail App on my phone and those programs don't have any problem connecting with Exchange. At this point in the 21st century, it should be no surprise to the developers of the Apple Mail program on Mac OS that many people are buried in a daily avalanche of emails.

This is a very helpful forum for discussion of this problem. I also wanted to emphasize the bizarre intermittent nature of this issue for anyone talking with Apple. I have had exactly the same problem that has been described here using Catalina. But yesterday it flipped back to no issues at all. It is syncing perfectly, functioning just like my iOS mail. I did nothing to cause this. I imagine that one day it will stop working again, unfortunately. But for now it is a nice reminder of how sweet it is when it actually works as it is supposed to. 

Just to add to this discussion: I have the sync problem as well, and *I do not have any IOS devices*. I have been using MacMail and Office 365 without incident for some years (since my company decided to disable IMAP off-site :( ) and in the last few weeks it's regularly simply stopped syncing.

For me, reducing the number of emails I have is not an option: yes, I clean up, but I also save a lot - as I need them for later (and as a general point: a fix should not be "change the way you work", it should be "fix the software"!). Others I know have had the same issue, and deleting/remaking the account only worked as temporarily: I'm not in a hurry to fix it.

Of course, part of the problem is Microsoft using a proprietary protocol, but since Outlook is so unbearably horrible, and mind-blowingly stupid (when I open it because Apple mail has stopped, it feels the need to remind me about every meeting in my calendar prior to now that I have not yet been reminded of by Outlook itself), it really is imperative that Apple get this sorted.

Another update. This morning, my Exchange calendar events in Mac Calendar were unresponsive, so I quit calendar. It then restarted on its own and worked fine. So, I fired up Mac Mail, and boom. It synched with Exchange mail. The only things that I did yesterday as an attempted fix were to (1) delete the saved state files in Mail's Application Saved State folder and (2) turn off VPN. They seem to be coincidental. When Mac Calendar restarted on its own, it seems like something within the OS rebooted itself, and it had nothing to do with anything I did. As far as deleting the saved state folder, I suppose that could have helped kick start Mail, but if it did, it took a long time and multiple restarts of Mail over the course of 24 hours. As far as VPN, I suppose that could have been part of the issue. At the time Mail synched, VPN was not connected.

Like SiliconeCatastrophe, I do not have any iOS devices, but my MBP (Retina, Early 2015, running macOS 10.14.6) is showing this behaviour too.

A couple of weeks ago, Mail from my work Exchange server stopped syncing to the Inbox, although I could still send from the account. I would get an occasional burst where it updated, but unpredictably and roughly once a day. Forcing a rebuild of the mailbox got the mail to appear. Deleting the account and replacing it did not seem to cure it - obviously that triggers a mailbox build, so new mail appeared but was not syncing after that.

I started trying other clients (Spark too intrusive, Thunderbird worked fine but not a fan of the interface) and then Mail started working again. Until yesterday, when it stopped syncing again.

Today mine is miraculously working again and I have done nothing except stop checking my emails on my phone?!

I am purely using the mobile for calls whilst working at my desk, so less requirement for both devices to refresh. Perhaps browsing emails on the mobile is a habit to be avoided.

Just try sticking to one device at a time.

I also wondered if it gives up the sync when the demand on the wifi is very high (extra people working from home in the area, school kids streaming etc). This seems to be the only explanation???

It would be nice if an Apple expert/developer could comment on here and clarify this.

and out of nowhere also my iMac suddenly stopped syncing my Exchange inbox again....That's now 20 hrs ago and the only way to receive new mail (other than via iOS devices) is restart the Mac. Or using Outlook which for me is halfway going back to windows again.

great all these fantastic Apple products, watch, new glasses and the like but they better make email work or else its all useless to me. Apple in a corporate environment just s@cks i think.

I havent bothered yet to start reconfiguring the Exchange account again (as this usually works). Many years ago I made the switch to Mac for the ease of use and reliability but it starts to reverse, especially when i read how many users have been experiencing the same issue and with Apple doing zero. I will now just wait and see what happens and meanwhile use Outlook. Maybe i will get used to using Windows again

Yep, mines the same.

Nothing at all yesterday, this morning it’s been behaving perfectly, and I’ve been accessing email on my phone as well so it’s nothing to with that.

not going to ask why, I’m just happy it’s working again and I can stop with outlook!

Thanks to everyone for all the assistance