My iCal app in Mac OS Yosemite is not working

Hi EnioKlein,

Welcome to the Support Communities! I realize how important it is to get your iCal / Calendar app working properly and syncing with iCloud. The comprehensive troubleshooting guide below should help you get back on track. Take a look at the Mac OS X section and follow the steps in order to resolve your issue.

iCloud: Troubleshooting iCloud Calendar - Apple Support

Confirm that you've turned on iCloud Calendar:

1. Choose System Preferences from the Apple menu (), then click iCloud.
2. If you're using OS X Mavericks v10.9 or later, make sure that the Calendars checkbox is selected.
3. If you're using OS X Mountain Lion or Lion, make sure that the Calendars & Reminders checkbox is selected.

Try each of these steps, testing after each to see if the issue is resolved:

• Make sure that you are using OS X Lion v10.7.5 or later. Learn how to verify the version of OS X you are using.
• Make sure your computer is online. Attempt to view www.apple.com. If you can't connect to the Internet, your iCloud calendars and events will not update in Calendar or iCal. Learn how to troubleshoot your Internet connection.
• Open a secure website to test if ports 80 and 443 are accessible. Calendar requires port 443 access to iCloud in order to push and fetch updates to and from the iCloud Calendar servers.
• Choose Apple () menu > System Preferences, then click the icon for iCloud. Make sure that you're signed in to the same iCloud account that you're using on your other supported devices.
• Make sure that you enter and update calendar information in the iCloud section of Calendar or iCal. Only calendars and events in the iCloud section of the Calendar or iCal Calendar list are updated in iCloud. Both Calendar and iCal for Mac support the display of and interaction with multiple accounts and datastores, such as iCloud, On My Mac, Exchange, and Google. This makes it easy to create or modify events or calendars in a section of Calendar or iCal that may not be updating iCloud. Learn more about moving local calendars to iCloud.
  • In some cases, you may find that you have data duplicated in both the local On My Mac and the iCloud sections of Calendar or iCal. Learn more about resolving this issue.
  • You can make the iCloud calendar your default calendar for all new events. In Calendar, choose Calendar > Preferences, then click General. In iCal, choose iCal > Preferences, then click General. Locate the Default Calendar setting and choose one of the Calendars under the iCloud heading. Close the Preferences window to save the change.
• If recent changes don't appear, try forcing Calendar to refresh by selecting Refresh Calendars from the View menu. In iCal, select Refresh or Refresh All from the Calendar menu.
• If you've recently made changes to your contacts' birthdays and are not seeing those changes reflected in your Birthdays Calendar, try to refresh your calendars. If you made the changes in the Contacts app on an iOS device or at iCloud.com, it may take up to an hour for those changes to appear on your other devices.
• Make sure that your account was successfully created in Calendar (or iCal) on your Mac. After upgrading to iCloud Calendar, you may need to quit and reopen Calendar (or iCal). To confirm that your account is configured correctly in Calendar (or iCal):
  1. Open Calendar (or iCal).
  2. Open Calendar (or iCal) Preferences.
  3. Click Accounts. You should see an account with your iCloud member name in the Apple ID field.
• Turn iCloud Calendars off and back on:
  1. Quit Calendar (or iCal).
  2. ChooseApple () menu > System Preferences, then select iCloud.
  3. Deselect the checkbox next to Calendars (or Calendars & Reminders in Mountain Lion and Lion).
  4. Close System Preferences and wait about a minute.
  5. Open System Preferences and select iCloud.
  6. Replace the checkmark next to Calendars (or Calendars & Reminders in Mountain Lion and Lion).
  7. Close System Preferences.
  8. Open Calendar (or iCal) and test to see if the issue is resolved.
• Restart your computer. This may sound simple, but it reinitializes your network and application settings and can frequently resolve issues.

Troubleshooting at iCloud.com

• Check iCloud Help (help.apple.com/icloud) for possible information about the issue you are experiencing.
• If you're having trouble with the web-based iCloud Calendar at icloud.com/calendar, the first place to start troubleshooting is your browser. Learn how to troubleshoot browser issues for a variety of web browsers on multiple operating systems. Browser troubleshooting should never be skipped for web-based issues.
• If you are seeing issues with the iCloud Birthdays calendar, remember that it updates hourly, so it may take up to an hour for changes to the birthday field in iCloud Contacts to be reflected in iCloud Calendar.
• If you encounter an issue while using iCloud Calendar on the web, a message may appear with a "Send to Apple" button. Clicking this button helps iCloud to track issues and create fixes.
• If updates from other devices do not appear, or the Calendar interface does not appear as expected, switch to another application by clicking iCloud in the upper-left corner and selecting the application you wish to use. After visiting a different app location, such as Contacts, switch back to Calendar. If issues persist, you may wish to sign out of iCloud by clicking on your name in the upper-right corner, signing out, then signing back in.
• If you've recently made changes to your contacts' birthdays and are not seeing those changes reflected in your Birthdays Calendar, try switching to another iCloud application, then back to Calendar. If you made the changes in the Contacts app on an iOS device or on your Mac, it may take up to an hour for those changes to appear on your other devices or on iCloud.com.

I hope this information helps ....

- Judy