I use Mavericks and want to change the default behaviour in Calendar when a new Event is created. In the preferences it is possible to change some of the settings. But I would like to get two default alerts and no "basso" sound (Only "Message" not "Message with sound"). I Already found that in ~/Library/Calendar/ are folders for each calendar and every calendar seems to have its own settings in its LocalDefaultAlarms folder: "EventAllDayAlarms.icsalarm" and "EventTimedAlarms.icsalarm".

But I'm not able to change these files. Or to say it more clearly, I can change them, but each time Calendar is restarted, they change back to the state before. Besides that, it is the same with the Info.plist file.

So, is it possible to prevent Calendar to update these files? Or is there a better method to change these settings?

  • The limited way to set alerts in in Calendars Preferences under Alerts. There you can set some defaults for each account. This is why the alter prefs are listed for each account in the Library. The actual sound is, by default, the alert sound set in the system Sound Preferences. You can further tweak the alert for each event by electing "custom" alerts for each event. This doesn't exactly answer you question, but should let you know what you are working with.
    – sdmeyers
    Aug 12, 2014 at 14:47

2 Answers 2


As far as I know, these are the only two ways to change Calendar alert sounds. In both cases, unfortunately, they are universal changes—there is no way to override them for individual events.

Disable all Calendar alert sounds

Go to System Preferences > Notifications > Calendar and disable "Play sound for notifications."

system preferences

Change all Calendar alert sounds (pre-El Capitan)

We'll be digging around in System a bit, so be prepared to enter your password a couple times. I'm on El Cap now (my only Mac), and this isn't working for me, but I know it worked in the past. My guess is System Integrity Protection. This should probably work if you're on an earlier version or have SIP disabled; let me know if it doesn't.

  1. In the Finder, go to /System/Library/Sounds
  2. Change the name of Basso.aiff to something like Basso-original.aiff
  3. Add a new audio file of your choice named Basso.aiff

I struggled with this for days. For me, the problem was that I REALLY didn't want to change the sound for all alerts because Basso is fine for basic system alerts. I just wanted to change it for the Calendar alerts and not for everything. Apparently some things that used to work, do not work on Sierra, but this did.

  • Find a new aiff file (here are some examples http://tdwhs.nwasco.k12.or.us/staff/lewing/resources/sound_effects.htm)
  • Download the file and rename it to something like Alarm.aiff (multiple words may work, I didn't try)
  • Open the terminal (/Applications/Utilities/Terminal.app)
  • Copy the file to ~/Library/Sounds using something like the line below (assuming you download the aiff file into your Downloads Directory)

    cp ~/Downloads/Alarm.aiff ~/Library/Sounds

  • Quit iCal.

  • Copy the line below into the Terminal window and press return (Match the last parameter "Alarm" to the name of the file you copied above)

    defaults write com.apple.iCal 'Default alarm sound' 'Alarm'

  • Open iCal, new default alarms should now use that sound.

This worked for me and now I have a different alarm sound Only for iCal. If I could change the location of the notification alerts to the middle of the screen (again, for iCal only), I would be even happier.

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