Using shared calendars on a Mac or iPhone

How to see and edit a calendar somebody has shared with you, on macOS and on an iPhone or iPad.

Apple’s Calendar app reaches Zimbra over CalDAV. On a Mac that gives you full use of calendars shared with you. On an iPhone or iPad it does not, because iOS has no support for delegated calendars, and that one limitation explains everything below.

Setting up the account on a Mac

1. Open Calendar, then its settings, then Accounts.
2. Click the plus sign and choose CalDAV as the account type.
3. Enter your full email address as the username, then your password and the server address.
4. Let the account verify. Your own calendars appear in the list shortly afterwards.

Adding a calendar shared with you

Accept the share in webmail first, and check you can see the calendar there. Then open Preferences, then Calendar, and turn on delegation for the Apple CalDAV client. Save and close preferences.

Back on the Mac, open Calendar’s settings, then Accounts, select the CalDAV account, and open the Delegation tab. Everything shared with you is listed there. Tick the calendars you want, close the settings, and they appear alongside your own. You can edit them.

On an iPhone or iPad

iOS has no equivalent of the Delegation tab, so two things follow from whichever way that setting is left.

With delegation turned on, calendars shared with you do not appear on the device at all.

With it turned off, they appear but are read only. You can see the appointments and not change them or add any.

Shared calendars never appear over ActiveSync, whichever way the setting is left.

An unsupported way to edit a shared calendar on iOS

The steps below are a workaround rather than a supported arrangement, and you follow them at your own risk. They point a CalDAV account at somebody else’s mailbox instead of your own, so the device shows that mailbox’s calendars in place of yours.

1. Accept the share in webmail and confirm it works there. Give the calendar a name you will recognise, because that is how it appears on the device. Delegation can be on or off for this to work.
2. Set up a CalDAV account on the device for your own mailbox and let iOS verify it. Confirm your own calendars appear before going further.
3. Edit the account. Under the advanced settings, find the account URL, which reads something like /principals/users/yourMailbox%40yourdomain/.
4. Replace yourMailbox%40yourdomain with the shared mailbox, giving /principals/users/companyshare%40example.com/ or similar.
5. Go back to the main account screen and tap Done. The account verifies again.
6. Open Calendar. The shared calendar is listed, under the name you gave it in the first step.

The same change works on a Mac, where the field is called Server Path. Quit Calendar and clear its cache afterwards, or it carries on showing the old list.

Clearing the Calendar cache on a Mac

Calendar keeps its own copy of the calendar list, so a change made on the server sometimes fails to show. Clearing that copy forces it to rebuild.

1. Quit Calendar.
2. Move ~/Library/Calendars/Calendar Cache somewhere else, so you keep a copy.
3. Delete the original.
4. Open Calendar. It rebuilds the list from the server.

For sharing a calendar out in the first place, and the roles you can grant, see sending as another address, or on behalf of someone else.