Currently Being ModeratedAug 30, 2013 7:40 AM (in response to LynneFranco)
I had this exact issue after migrating to a new iMac. I tried the following recommended on another post:
Quit iCal. In Finder, from the Go menu select 'Go to Folder...'. Enter the path~/Library/Calendars/ . A new Finder window should open. From that window move the file Calendar Cache to your Desktop. Re-open iCal.
But I had elsewhere has permissions issues caused by the migration. So I went to the folder about. Clicked on "Get Info" in Finder - and gave myself (my user) explicit permission to read write - and applied this to all folders and files within the folder.
Hope this is useful to someone.