Q: My iCal on my Macbook is not syncing after installing Yosemite

I was also having this very same problem. My techtective work led me down a trail of gigabits and megacrumbs where I found an app on the app store called CalendarPro for google. Although it is 2 bucks and lame that the regular calendar is not able to sync up, it was worth it to me to have my calendar linked to my laptop. I hope this helps some of y'all.

Thanks for the very comprehensive response!

I have followed your advice to the letter, step by step. No joy.

I'm running OS X 10.10.2 on a 2013 iMac.

My shared iCloud calendars have worked as advertised, except that I cannot now add people to an already successfully shared calendar.

When I open Calendar, I now see the little warning triangle next to 'iCloud" at the top of the sidebar.

Previously (pre-Mavericks?), a calendar with sharing problems had its own triangle, but now it seems to be the whole iCloud group.

NONE of my previously shared calendars permits sharing; I created a new calendar in the iCloud group to test the problem. It appears on my other devices, but it, too, will not share.

While the test calendar appeared on my iPad, iPhone iCloud (and could be edited on all four), it can't be shared.

I've tried all the fixes I can find in Support and these discussions (there aren't many), to no avail.

Any fresh clues very welcome - thanks.

This helped me.  I think it was Go to "View" in the Calendar and "Refresh" after I did all of the other items in the process

I Have had apple kit for years so there's some legacy... I found I was signed in as @me.com on iOS and @mac.com on the macs.... I changed them all to the top hierachy .mac after deleted all the icloud accounts and everything is sweet

Don't you lose all your saved documents when you delete an account,though? This sounds a bit scary!

PERFECT! I created a Test event on my iPhone and within a few seconds, it updated with all of the other events I had created on my Mac. Winner!

I'm thinking of doing the same thing and getting another calendar app for my laptop. I don't think Apple wants to support Calendar on non-mobile devices anymore, so I'm guessing we will never get a true fix for this.