I realize I am adding to a thread that is almost a year old but…
I also experienced the ical unexpected crash after upgrading one of my iMacs to Leopard from Tiger. This was after having upgraded 6 other (each less than 18 months old) macs (various models) without any problem.

I found many references to this problem and they seemed inconclusive in that some things worked for one person but not another. The solution I describe below did work for me and is more specific to the Apple OS-X System data structure than the other solutions I found in that the files which iCal is upgrading are actually moved to their expected location.

I believe the problem and the solution to this iCal problem may be identical to similar problems people have reported with using other Apple applications (i.e.: iPhoto) after the upgrade.

The problem seems to be caused by a change (by Apple) in the location where Leopard looks for your iCal data as compared to where Tiger expected the data to be. Perhaps an even earlier version of OS-X was responsible since all USER DATA on the problem machine had migrated through several computers over the last couple of years. In any case, if the structure was from a pre-Tiger mac then at least Tiger was able to handle it while Leopard actually moves it’ location during the upgrade.

In earlier versions I found the data in user/library/application_support/ical but in Leopard the required files are in user/library/calendars so I moved ONLY THE DATA FILES (dot calendar files) from the user/library/application_support/ical/ to user/library/calendars.

SO THE FIX:

MOVE ALL DATA FILES (those which start with an alphanumeric string and end with “.calendars” from the ~user/library/application_support/ical/ folder to the ~user/library/calendars folder.

A final note:
It may be that the real culprit is the adding of a calendar event to your system from another system. In my case debugging revealed that an “unexpected end of file” generated the “unexpected quit” of iCal. I have seen reports by an individual who said he/she felt it was caused by the import of an EVENT which was generated by Lotus Notes on a PC/Win machine. That sounds likely to me and I have extensive programming and debugging experience as a computer professional. That’s my guess for now.

I hope this helps someone else. Thanks to everyone who took the time to share their knowledge, including those people who acknowledge it worked for them.

Soon we will have a new operating system and this will become moot. See you then with the new exciting problems! Ha!

Though the first fix didn’t work, removing the sync folder worked wonders.

Again,

Thanks!

ideas?

email to:
spygirl(AT)att.net

Still wish I could get iCal to function.

Sincerely,
KShapiro