Calendar or Reminders alerts don't pop up on your Mac

Why it happens

Calendar and Reminders can only pop up if their notifications are allowed and set to show on the desktop. A Focus like Do Not Disturb also silences them quietly. And an event with no alert set, or a reminder with no time, never notifies at all.

How to fix it

1. Open the Apple menu, choose System Settings, and click Notifications in the sidebar.

2. Click Calendar in the list of apps and turn on Allow notifications.

   Notifications›Calendar›Allow notifications

3. Make sure Desktop is selected so alerts appear on screen. Pick Temporary for alerts that slide away by themselves, or Persistent for ones that stay until you click them.

4. Go back, click Reminders, and do the same: Allow notifications on, Desktop selected, and your choice of Temporary or Persistent.

   Notifications›Reminders›Allow notifications

5. Check the event itself has an alert. Open it in Calendar and set Alert to a time, like 15 minutes before. A reminder needs a date and time to notify you.

Still not fixed?

1. Is a Focus on? Click Control Center in the menu bar and look at Focus. If Do Not Disturb or another Focus is on, turn it off, or add Calendar and Reminders to its Allowed Apps.

   Focus›Do Not Disturb›Allowed Apps

2. For alerts that should break through a Focus, turn on Time Sensitive alerts for Calendar in Notifications. On macOS 26 it's called Allow time sensitive alerts, and on macOS 27 Time Sensitive Notifications.

   macOS 26 Tahoe Notifications›Calendar›Allow time sensitive alerts

   macOS 27 Golden Gate Notifications›Calendar›Time Sensitive Notifications

3. Set a default alert so new events always remind you. In Calendar, open Settings…, click Alerts and choose a time for Events.

   Calendar›Settings…›Alerts

4. If alerts arrive on your iPhone but not your Mac, check the calendar is ticked in the Calendar sidebar on your Mac and that you're signed in to the same account.

5. If nothing pops up even with all of this set, restart your Mac and test with an event a few minutes away. If it still stays silent, contact Apple Support.