Leopard has a very annoying bug that if you delete a calendar in iCal it will notify everyone you have ever invited to an event… that’s everyone. So if you have a years worth of events, expect to send out a couple hundred emails. This makes it very problematic if you want to migrate a static calendar to say Google Apps, or… I don’t know, just want to delete an old calendar!

I’ve tried to go in and delete the calendar files and iCal cache, but since I use .Mac syncing they keep popping back in, even after I have turned off .Mac syncing they still come back.

The only way I figured I could do it without sending a million meeting cancelations was to delete the calendars while unplugging my Mac from the network. Then trying to delete the messages while offline. Due to bad timing on my part I missed a few before they got sent out.

Its not often when you notice such a bad usability bug in Apple’s products, but this one is a doozy, since it isn’t just an annoyance to you, but to others who get your cancelation spam.