Changing iCal’s Default Alert Sound (Mac OS X Lion)
- Download and install Xcode from Apple.
- Quit iCal if it is running, and open your user Preferences folder. (Easiest way to open it is to use Finder’s Go menu; press and hold the Option key and you will see Library folder; click and open it; the Preferences folder is in there.)
- Open the file named com.apple.iCal.plist with Xcode.
- Right click (or Control+click) anywhere in the window, and select “Add Row”
- Edit the created row as follows: Key=Default alarm sound, Type=String, Value=Glass (the last value can be changed with the default sound of your choice).
Update: This doesn’t work on Mountain Lion (Mac OS 10.8).