If you’ve been using Mac Calendar for many years there is a good chance that you have many more calendars to choose from than you need. Back before iCal became simply “Calendar” there was a “+” button that many people thought was to create a new event, but it was to create an entirely new calendar. This gave many people several calendars that may or may not be empty.
If your calendars are stored in iCloud, Exchange, Office 365, Yahoo, or AOL the latest macOS Sierra introduces a way to easily merge them.
- If you don’t see the list of calendars on the left column of the Calendar app click the “Calendars” button in the top left corner.
- Drag one calendar on top of the other. Both calendars must be in the same account.
- You’ll notice that the mouse cursor will change to a curved arrow. If you release the mouse button there Calendar will ask you if you’d like to merge that calendar into the destination.
If you’re using Google for your calendar server, however, you will need to use their web interface to export calendar data and import it into the proper calendar, then delete the source calendar.