How can I change the default alerts of Calendar (iCal)? 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?
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."



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.


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