ICal keeps sending alarms for past events and won't let me delete items from calendar, I hit delete but the event just keeps multiplying on my calendar?

Question

iCal just started repeatedly sending me alarms a couple of days ago. I thought deleting the event from my calendar would help but it won't let me delete them, they just keep multiplying in my calendar. Help please

Answer 1

Hello again,
Well I seem to have overcome the problem, but not easily, and not by identifying the cause. I don't like that I don't know what caused the trouble. I make no guarantees, but this is what I did (on an iMac with Snow Leopard 10.6.8). Be sure to create backup copies of your files first:
[Note: before you do any of this, you may want to try running Disk Utility program (found in Applications/Utilities/) and run the "Repair Permissions" option. See if that solves anything, but it didn't for me]
a) I exported my iCal as an archive: Menu item, "File/Export/iCal Archive...". This won't likely do you any good, though, as something was wrong with it and I could not re-import it. But try anyhow.
b) After backing them up, I deleted the folders and contents inside the Calendars folder: "Users/<your user name>/Library/Calendars/<subdirectories>". To create a backup, right-click on the Calendar folder and choose "compress Calendars" from the pop-up menu. Then drag the folder contents into the trash.
c) After creating backup copies, delete (drag into the trash) these preferences files found in "Users/<your username>/Library/Preferences" (the slashes delimit the folder names):
  Users/<your username>/Library/Preferences/com.apple.iCal.plist
  Users/<your username>/Library/Preferences/com.apple.iCal.helper.plist
  Users/<your username>/Library/Preferences/ByHost/com.apple.iCal.helper.<some convoluted hex number>.plist
d) Restart your computer;
e) Launch iCal and reimport the individual calendar files you exported earlier.
Hopefully all is well.
Let me emphasize again that you will not likely succeed in reimporting the calendar archive. In the first place it likely contains corrupted data that caused your trouble in the first place. So you will need to import the individual calendars that have been exported. Be very certain to export these individually first.
And if you want to make doubly certain, then copy and paste some of your important and key events into a TextEdit file and save that file in case you don't succeed.
Perhaps you subscribed to some online calendar? If I recall correctly I had imported a calendar when the World Cup Soccer series was happening; I speculate that might have contributed to the issue. I wish I could have found exactly what caused the trouble. It may have been some older, less compatible format that was retained through a series of Mac OS updates.
Good luck.