Apple Calendar allows setting a default alert for events, including all-day events. But with all-day events there is no obvious way to control the time of the alert. Calendar preferences for alerts

All options displayed in the UI are for 9AM.
options for default alert time

This is mind-bogglingly restrictive. If I want to be alerted the day before an event, or two days before an event, I would never want to be alerted at 9AM—that's when I'm either sleeping or thinking about what I need to do that day.

How can I change this? Can I get more granular control somehow with defaults write? Or is there some other way? (A background process that detects new events added to my calendar and fixes their bad defaults?)

  • Third-party calendar clients can. I know Fantastical allows you to change defaults. It integrates with Apples Calendar and will show in Calendar App. If think is uses custom to apply its defaults. The other option is using an Apple Shortcut to create new events. you can make an event that has a custom alert. As for defaults write/read I don't know, a lot of the old settings no longer work or have changed in newer versions of macOS. Also if you cannot change such preferences in the GUI it makes it very difficult to find them in the system. If I do find a way I will answer.
    – AndrewC
    Jan 4 at 19:40

1 Answer 1


This question is for previous macOS version.

The time can be changed in macOS 10.14.3 Mojave:

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  • 1
    OP is looking for a way to set the default for all day events.
    – samh
    Feb 19, 2019 at 21:28
  • 1
    Yeah. That option is not present in macOS Calendar. Should I delete my answer?
    – modlin
    Feb 19, 2019 at 21:43

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