macOS Calendar, Reminders, and BusyCal can each display alarms for your Events and To Dos. You should disable the alerts for macOS Calendar and Reminders to prevent receiving two alarms for every event — one displayed by macOS Calendar or Reminders and another displayed by BusyCal.

BusyCal 3

If you have BusyContacts installed, BusyCal will read in birthdays from BusyContacts. So you will need to launch BusyContacts while BusyCal is running to read in any recently updated Birthdays. If you have BusyContacts installed but are not using it or it is expired, you will need to drag the BusyContacts app to the trash. Then BusyCal will pull birthdays from Apple Contacts instead.

If that doesn't solve it, please toggle these checkbox settings in BusyCal Settings to see if that solves it:

• BusyCal > Settings > General > Show Birthdays calendar
• BusyCal > Settings > General > Show Anniversaries calendar

If that doesn't work, then it might be due to the fact that BusyCal requires access to Contacts for displaying the Birthdays calendar and processing meeting invitations. The first time you launch BusyCal you should be presented with a dialog asking if you want to grant BusyCal permission to access your contacts. Perhaps you clicked Don't Allow?

To fix this, open System Settings > Security & Privacy, select Contacts in the left sidebar, then check BusyCal.app.

BusyContacts

BusyContacts has a Show Dates in Calendar feature for controlling which birthdays to display so that your calendar is not overwhelmed with unwanted birthdays from Facebook or LinkedIn. In BusyContacts, go to BusyContacts > Settings > Info Panel, click on the Show Field popup and make sure Show Dates in Calendar is checked.

Then, in BusyContacts select the contact who's birthday or anniversary you want to show in BusyCal, go into Edit mode and make sure the Show dates checkbox is checked for that card. Once it's checked, the birthday and/or anniversary for that card will show up in BusyCal.

You can learn more here:

https://support.busymac.com/help/47353-birthdays-and-anniversaries#show-dates

BusyCal 2

You should be able to solve this birthday duplication in one of these ways:

A) You may have some corrupted cached Birthday data. Uncheck the Show Birthdays calendar preference in BusyCal > Settings > General, and quit BusyCal. Then launch BusyCal and re-enable the Birthdays calendar in BusyCal > Settings > General. Hopefully that will clear it up.

If that doesn't work, please try this:

B) You may have duplicate contacts in macOS Contacts. This might happen if you have contacts (with birthdays) stored both locally On My Mac, as well as on iCloud.

The duplicate may be hidden in macOS Contacts. You can verify that a contact is duplicated by an attribute in the Contact Card called "cards" in gray. If this entry lists "On My Mac" and "iCloud", then that contact is on both lists.

You'll need to delete the duplicate local contacts that are stored On My Mac, so you only have one of each contact stored on iCloud. In macOS Contacts, click on the "All on My Mac" header in the Contacts sidebar, then delete any contacts under that list that are also listed under All iCloud.

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