After setting up iCal and adding birthdays and other events in my contacts. I now have duplicates of everyones birthdays showing.
I have tried several things but can not delete the duplicates.
MacBook Pro with Retina display, OS X Mountain Lion (10.8)
You actually have hidden duplicates in your Address Book that you are unaware of; I had the EXACT same problem. I downloaded a program called Bento (http://www.filemaker.com/products/bento/mac.html) and it allowed me to edit my Contact cards. iCal duplicated every single contact I had (and thus doubled the birthdays in my calendar). This allowed me to delete one of the two files (although only one appeared in the Contact app) and my birthdays went back to normal!
How do you get rid of birthday duplicates?
