Ventura not syncing exchange/outlook calendar entries

I've had this under Monterey already (and it fixed itself on some update, somehow), but it now cropped up again under Ventura.

For me, a /kill of exchangesyncd ends up being only a partial fix, as symptoms will re-occur (calendar will stop syncing) after a short while. So, after looking into this thoroughly, here's what has worked for me and has fixed this for good. I've been running without the problem for a couple of weeks now.

• If you have the issue the way I had it, then exchangesyncd will manifest 35%+ of CPU load and together with the calendar daemon basically solidly load your efficiency cores (see Activity monitor). That, btw., has side effects on other things like backup (slow) mail (slow), etc., so don't try to work around the issue by restarting it every hour in cron. :) Also, btw., eventually the system scheduler process will realize this issue and quietly kill exchangesyncd... which is when things stop syncing.
• After much digging into what it's actually going on when it churns like that, it seems that the culprit is the sql database that keeps the appointments locally. It is in a faulty/corrupted state post the OS upgrade. Obviously not something you can manually fix, so I went to remove it (so it'd rebuild itself).
• I quit the Calendar app, then deleted my Exchange Account (System Preferences). Then I deleted the database files.
• The three files to delete are: ~/Library/Calendars/Calendar.sqlitedb* - so the three files in there that start with "Calendar.sqlitedb".
• Now, reboot, for reasons. :)
• Then, re-establish your Exchange account, the database files will re-appear, after some syncing (could be an hour) you should be fine and exchangesyncd should be running in th slow single CPU% digits. Enjoy.

• BUT! Side Effect: If you are running iCal calendars in parallel to your Exchange calendar in the native Calendar app (and if they're running secure), then the removal of those database files will also delete required access data from the Calendar app's reach (the app will throw an error for iCal calendars that are switched on). To fix that secondary issue, you'll need to log out of iCloud entirely on that machine (System Preferences), reboot, then log back in. This will re-create the needed access data. Voilà.

I had this same issue when I upgraded to Ventura. I found there is a process called exchangesyncd that controls the sync with the calendar app (and probably other things like contacts, notes, etc). The point is that I was able to go into Activity Monitor (use CMD + Space and type activity monitor in the search bar), and then type exchangesyncd in the search field within Activity Monitor, do a force quit on it (select the process on the list and then hit the X shaped button on top then force quit). It will take several seconds for the process to restart by itself, and then a few more seconds for the sync to start working on the calendar app. It took maybe 20 seconds in my case to start seeing the calendar sync again.

I remember back in Monterey I had this issue pop up every now and then. A full restart would fix it, but then I found a process called calendaragent and I would do the same thing I described above. Calendaragent is now gone in Ventura, but my guess is that exchangesyncd replaces it, as it behaves the same way. Hope this helps out!

TomixM's solution worked for us: Ventura not syncing exchange/outlook cale… - Apple Community

When the macbook starts up the exchangesyncd process will show it's utilizing 40-60% of the CPU continuously. Killed the process and opened the mac calendar, refreshed the calendars and the process showed 2.5% CPU during the sync and quickly returned to 0%. Verified in Outlook365 online that calendar items added in the mac's calendar are showing up in outlook online.

Apple, get it together.

Today I found this page: https://macreports.com/exchange-calendar-sync-not-working-in-macos-monterey/, and the steps presented there solved the problem for me (Ventura 13.2):

1. In Calendar, go to top menu bar "Calendar" and open Accounts
2. Un-install the Exchange-account
3. Restart the mac
4. Install the Exchange-account again

Just had another account switch over to Outlook 365. I can't even log in because I get the issue below. I never got my calendars to sync on my other account so I'm done. I've switched to Outlook on my iPhone and Laptop.

Any luck fixing this? I've deleted my account completely, restarted, added it and still no luck. I also get time sensitive notifications from my own recurring event that I clear and they continuously pop back up.

Totally agree. Apple was very sympathetic and I demonstrated the issue to them which they documented. They took it to Apple engineering who then pointed the finger at Microsoft, who pronounced that exchange is working correctly. This is not customer service.

This problem already existed before Monterey. It is just getting worse.

The problem started with around macOS 11.

You can sync, after some days it stops syncing with exchange. You have to remove the configuration with exchange, reconnect, then it works again for some days.

Since Monterey it sometimes works only for hours.

Maybe since Ventura it is broken completely. (I have not updated yet)

I had already several cases opened, none of them were solved.

This worked, after a fashion, on Monterey. This stopped working on Ventura. I would not be expecting that this is Microsoft's fault.

I bend over backwards to use a Macintosh in a business context. This means that shared calendars and email should work flawlessly.

Apple needs to take more seriously, the use of Apple MacOS and iOS devices in a business context. Sadly, that usually means in a Microsoft world. Get with it, Apple; we want you to succeed!!

I have upgraded to Ventura now and to be honest, it looks to be stable now.

I'm using Exchange (Microsoft 365) as the company account, besides of the iCloud accounts with my family.

I have configured Microsoft Office (Outlook) and Apple-Mail/Calender/Contacts/Tasks to the Exchange-Online Account.

I'm using both in parallel (I like the overview in Apple-Calender).

Since the upgrade to Ventura, Apple-Calender is syncing without any problems. But we will see if it still syncs in a few days.

After the update of Ventura to 13.0.1 the problem is still present: the calendar does not synchronize with Exchange / Microsoft 365.

Please Apple, fix this as soon as possible! It doesn't have to be difficult, because until recently the synchronization was working perfectly ...

After reading the activity monitor tip I tried to use that, but I had no exchangesyncd activity, but under calendar I found one about ical weather. I killed that off and suddenly all my calendars came back almost instantly.

Worth a try? It worked for me.

I am on Ventura.

I deleted and re-added my Exchange account under 'Internet Accounts'

For me, that seemed to fix it.

Well, except for Apple birthdays.

But interestingly, Exchange birthdays may be working. I had given up on that ever working.

I also tried to remove the Exchange account, then I restarted the macbook and finally I added the Exchange account again among the "internet accounts": it actually seems to work. Calendar syncs with Exchange again!