I have an iMac running Monterey and a Macbook Air running Big Sur. Both machines are set up to connect to my employer's MS Exchange server. For the most part this works fine. However, there are problems with using macOS Calendar to display and edit events in my Exchange Calendar.

I can create and edit events using macOS Calendar on either machine, and they are successfully sent to the Exchange Server (verified by logging into the MS web interface). However, they never appear on the other machine, even if I manually 'refresh' the account (Cmd-R). Similarly, if I receive a meeting invitation and accept it from one machine, it appears on the other as 'unanswered'.

I have tried deleting and re-creating the Exchange Server settings on both machines, with no success.

  • Welcome to Ask Different. Any chance the Exchange admins would be willing to enable IMAP for your account? I'm on Monterey and use IMAP to connect to an on-site Exchange server - it works like a charm (I also use EWS on another account, and haven't had any problems so far...). Upgrading your Big Sur Mac to Monterey may help, too. Newer macOS versions have improved compatibility with Exchange. Is that possible?
    – jaume
    May 12, 2022 at 7:15
  • 1
    @jaume Sadly the genesis of this problem is that IMAP access has recently been switched off 'for security reasons'... but an upgrade might be a good place to start.
    – avid
    May 12, 2022 at 10:12

1 Answer 1


I used to work at a law firm that used its own Exchange server and then migrated to MS Hosted Exchange. And what I found over the years was that the only reliable mail and calendar client for an exchange server was Outlook (app or web, either one).

Many people used the built-in iPhone mail and calendar apps and never had a problem, but a significant (but relatively small) percentage of users would have strange problems with calendar events. Sometimes there would be duplicate entries, endlessly repeating duplicate entries, and some that would not show up.

Also problems with the Apple mail app that would not update or not show the contents of some folders, and a number of other problems.

Most of these issues could be "solved" (usually, not always) by removing the account and re-adding it.

While the number of issues with Mac clients was low (we only had a few Mac users) the same "fix" had a similar effect as on the iPhone.

The only permanent fix I ever found for issues with mail/calendaring using the Apple mail/calendar apps with an Exchange server was to switch to using the (free) Outlook client.

Outlook was rock solid and the few people I talked into using it never had another problem.

I know this is not a great "solution" but the only one I ever found. And honestly the Outlook app (at least on the phone) is a pretty good email application. I used it for years exclusively to keep my work and personal mail/calendars separate and found it a perfectly cromulent mail app.

  • +1 for the correct usage of the obscure word "cromulent." I was very gruntled to read your answer. I've witnessed the same problems the OP mentions, and your solution has been my go-to answer for my clients who experience like issues.
    – IconDaemon
    May 12, 2022 at 14:30

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .