I have been using multiple calendars on a Mac Book running El Capitan but recently iCal stopped displaying birthdays and US holiday. It seems like anything that comes from outside iCal doesn't work, but anything created inside works fine. All of the calendars I use are enabled as always. I've tried unenabling and reenabling, but no luck. Oddly, I have iCal synced with my Google calendar, and everything displays there as expected, as well as on my iPhone 5. Also, printing the calendar includes the missing events. It only seems to be missing when looking at the calendar on the Mac. I'm thinking there might be some data corruption somewhere and some file needs to be refreshed, or something like that. It's doesn't seem to be a settings issue, and I've found nothing on the web that resembles my problem. Any ideas?