Calendar events lost

Greetings!

It sounds like your Calendar data may not be syncing properly between your Mac and your other Apple devices. Here are a few steps you can try to restore your missing calendar events on your Mac (If your calendar entry has been selected):

1. Check your internet connection: Make sure that your Mac is connected to the internet and that there are no issues with your network or Wi-Fi.
2. Check your Calendar settings: Open the Calendar app on your Mac and go to Preferences > Accounts. Make sure that your iCloud account is properly configured and that Calendars is selected under the "Use with" section. You can also try unchecking and rechecking the box next to Calendars to see if that triggers a sync.
3. Force a sync: To force a sync, go to System Preferences > iCloud and uncheck the box next to Calendars. Wait a few seconds, then check the box again to re-enable syncing.
4. Check for updates: Make sure that your Mac is running the latest version of macOS and that all of your apps, including the Calendar app, are up to date.
5. Restore from backup: If you have a Time Machine backup of your Calendar data, you can try restoring it. To do this, first quit the Calendar app, then open Finder and navigate to ~/Library/Calendars. Look for a folder called "Calendar Cache" and move it to the desktop. Then, open Time Machine and go back to a date when your Calendar data was still intact. Find the "Calendar Cache" folder from that date and restore it to the ~/Library/Calendars folder. Finally, reopen the Calendar app and see if your events have been restored.