A calendar I had set up in Calendar application has disappeared

Good day T.McD.,

Thank you for visiting Apple Support Communities.

It sounds like you don't see a calendar you added to the Calendar application on your MacBook Pro. I'm wondering if you're missing the calendar events, or the calendar itself in the Calendar List (View > Show Calendar List.)

If you see the calendar in the list, but don't see any events, try these steps from Calendar: Show or hide a calendar’s events:

To see a calendar’s events, select the calendar’s checkbox in the Calendar list.

To show or hide the events on all calendars, hold down the Command (⌘) key while you click any calendar’s checkbox in the Calendar list.

If the calendar itself is missing from the Calendar List and you're using iCloud Calendar, try these steps from Get help using iCloud Calendar - Apple Support:

Refresh your calendars

1. Open Calendar.
2. Choose View > Refresh Calendars.

If you're seeing issues with the iCloud Birthdays calendar, remember that it updates hourly. It might take up to an hour for changes to the birthday field in iCloud Contacts to show up in iCloud Calendar.

Check your default Calendar account

If you store and edit your events in the iCloud section of Calendar instead of another account section, like On My Mac, Exchange, or Google, iCloud will automatically update your calendars. Learn more about moving local calendars to iCloud.

If you use multiple accounts on your Mac like iCloud, Gmail, and Yahoo, make sure that iCloud is your default Calendar account:

1. Open Calendar.
2. Choose Calendar > Preferences.
3. On the General tab, make sure that one of your iCloud calendars is the default.

Turn off iCloud Calendar and turn it back on

1. Quit Calendar.
2. ChooseApple () > System Preferences, and click iCloud.
3. Deselect Calendars (or Calendars & Reminders on OS X Mountain Lion).
   On OS X Mountain Lion and Mavericks, when asked, click Delete from Mac.
4. Close System Preferences and wait about a minute.
5. Open System Preferences and choose iCloud.
6. Select Calendars (or Calendars & Reminders on OS X Mountain Lion).
7. Open Calendar.

Restart your computer

Restart your computer and check the issue.

Best Regards,

Jeremy