Using Apple Calendar to sync Microsoft Exchange Group Calendars

«I’ve noticed your calendar is empty for what remains of the month. Would you like me to begin planning.»
Alva in «Cyberpunk 2077»

If you work in a group, having a shared calendar can facilitate planning as everyone can add and change appointments (e.g., adding new people to group meetings or cancelling a specific appointment).

At work, we use Microsoft Exchange, which allows for group calendars (a resource). Once that calendar is created, the question remains on how to integrate it with Apple’s Calendar, which you can do via Delegates.

Just go to Preferences > Accounts > select the MS Exchange Account > select Delegation, then press the plus to search for the calendar.

The funny thing — it worked without a hitch for my colleagues, but I couldn’t not add it. It looked like Apple Calendar started the search and the immediately aborted it. Very, very annoying. I did remove the calendar info and tried a few other things, before I thought about editing the Preference File directly.

But as usual with problems like these, it payed to go a step back.

The app could not find any calendars … from my computer, but it could do so on the computers of my colleagues. Who also were accessing it from outside the VPN, so that wasn’t the issue. What else is different? I usually go through the settings and deactivate anything I do not need, which — when it comes to the work Exchange account, includes Contacts and Reminders. So perhaps the address book was at fault.

I activated sync of Contacts (and Reminders, just to be on the save side) in Internet Accounts:

And low and behold, it was possible to add the calendar.

Unfortunately, I could not activate the calendar, the “Show” button could not be clicked.

So I removed sync of calendar, cleared the calendar data from my notebook, restarted it, waited patiently until the sync of the calendar data was done, and then added the delegates again. And this time it worked.

Now the group calendar appears under Delegates. I usually leave these Delegates calendars folded in as apparently Apple calendar shows when they are refreshed and that animation (text color changes for a split second) is annoying. And if you want to have alerts, apparently the default for delegated calendars is “Ignore alerts”. Just deactivate it (right-click on the calendar itself — Get Info).

Not the easiest process (if you fiddle with the default settings), but hey, it works.