Before making any attempts at deleting calendar data, backup what you have just in case:
Click on each calendar on the left hand side of iCal one at a time highlighting it's name and then going to File Export > Export and saving the resulting calendar file to a logical location for safekeeping.
iCal has an automated function located in iCal > Preferences > Advanced > Delete events "X" days after they have passed. By typing in a value for days you can tell iCal to delete all events before that time frame.
Today is 4-16-2012.
If I wanted to delete all events prior to 1 year ago (4-16-2011) I would type in "365" for the number of days.
Once you type in the number of days you want kept in iCal, close the preferences and then quit iCal.
Re-open iCal and check to see if the events are gone. If not you may want to leave it open for several minutes and then quit again.
Once the events are removed go back to iCal > Preferences > Advanced > Delete events "X" days after they have passed and make sure the check mark is removed to prevent future deletion.
Hope that helps.
I have a question about iCal. I cannot do anything in my iCal, something is terribly wrong. All that appears is the events box with "cancel or ok" options. Every time I say ok or cancel another keeps reappearing. That is the only thing available. I cannot do anything in iCal. There is no way for me to choose anything other option from the menu bar or do anything else.
How do I clear EVERYTHING without deleting iCal?
When does the delete actually happen?
When I click on "Delete events xx days after they passed" I get a warning that iCal will delete events older than 30 days. You can't change the value of that until after you click Yes. So, if I click Yes, then change the days value (to 365, for example) will it already have deleted items older than 30 days?
Would like to know before I do this...
MadisonP, I tried your proposed method last night. While it worked, iCal sent out hundreds of meeting cancelation and decline emails for events that happened years ago. A little embarassing for me.
I would not recommend using the auto delete feature if you use iCal to send or respond to meeting invitations.