Q: iCal not syncing with Exchange calender in OS X 10.10.2

I have 3 exchange accounts linked to our office365 site. All 3 mail accounts work perfectly, however only one calendar is now sync'ing. The other 2 have stopped working for no apparent reason. I have tried all the methods I could find on the various forums, killing calendar agent, removing accounts, changing server names, deleting cache and none of this works. As soon as the calendars rebuild and start to try and sync, 2 accounts fail and one is ok. I administer the office 365 platform and there are no differences in the account types.

Completely baffled and frustrated as this seems to be an Apple issue!

Thanks for the reply but I can't locate this file or the calendar folder for that matter.   Sorry to be dense but can you provide the full path, the one above does not work for me.   Is there some specific view I need to be in with Finder to see it?

You aint being dense, took me ages to work out where stuff is stored on my mac :-)

When you open a finder window, there should be a Go Tab in the menu bar.

If you click on that, there should be a Go To Folder option at the bottom of the menu which brings up a path entry box for folder you want to get to;

Type the following in;

Should open up the calendars folder for you, you will see the calendar cache files in there;

Hope this helps.

ty this helped me

Thanks for the detail, I never would have found that myself.   I found the files and deleted them, emptied the trash, killed the CalanderAgent beforehand, restarted iCal and all of the other calendars repopulated and synched OK but Exchange still will not synch.

Any other ideas?   Really appreciate the help.

No worries, worth a try.

I'm in the same boat, have tried this procedure as posted on a number of other threads. Have also tried deleting the Exchange Account and re-adding. Also manually setting the exchange server url, but nothing is making a difference.

The really strange thing for me is that I have 3 exchange calendars all linked to our office 365 url, 2 of them are failing to sync and one is fine. Unfortunately the one which is working isn't really of any significance to me on a day to day basis :-(

I take it your mail is working fine? Are you linked to Office365 or an Exchange server?

We have a hosted Exchange service, not 365.   Works fine other than synching to Mac OSX.   My iPhone and iPad synch flawlessly, just iCal on the Mac is the problem.  

Apple, any input?  Looks like a bug.

I am also having the same issue. OS X El Capitan 10.11.3 iCal will not sync with Exchange server. I am able to set up iCal on iPhone and it will sync. I have stopped iCal, deleted the 3 calendar cache files and restarted iCal and it still come up with an Exclamation: "Calendar can't refresh events in the calendar. There was an error attempting to send your changes to the exchange server"

Looks like they have a bug then, I am also able to get access to the calendars via iphone, IPAD etc. Just El Capitan that is failing.

Come on Apple - Get the finger out!

I am also having this issue. It just began out of the blue.

iOS, Outlook, Sunrise, Busycal, Fantstical all work fine, only iCal has the problem.

Cleared caches, restarted computer, removed accounts, re-added accounts... Nothing.

I really hope they push an update for this soon, Exchange calendar support is a critical part of why many companies switched to Apple computers in the first place.

Is there a solution available for OS Yosemite that will fix iCal syncing to Exchange server?

Same issue here after updating to El Capitan 10.11.3 - only my work Exchange based Office 365 calendar is not syncing - I tried all the fixes/workarounds but nothing works... It is making Fantastical unusable as well (it pulls data from iCal)... Please Apple fix this ****...

So today I logged into iCal and it has synced with Exchange Server (the Exclamation is gone from the Exchange calendar tab on left side) The strange thing is that a test event I entered before it synced on iCal has now 12 copies on the date. Now I create a new event on iCal but it does not show up on my iPhone. When I create another event on my iPhone, it does not show up on iCal. Any ideas what is going on?

I went through all the steps in this thread, and was not able to resolve.  I then went through MS and Apple support which led me to create a new Yosemite Partition with a whole new OS.  The behavior reproduced.

Finally, I switched Outlook to list mode sorted by date on a Win10 PC.  I had calendar events in the 1600s!  I deleted these and everything started working again.  I thought I'd circle back and post it here to help others.  It may not be the cause of everyone's problems, but it helped me.

Here is my solution: After deleting the Calendar caches as explained earlier it was still not Synching properly. Then I deleted all my Calendar items from the exchange account. I use for this Outlook for Mac, but you can probably use anything, just be sure to delete EVERYTHING from the calendar. It is now synchronizing perfectly between Mac Calendar, Outlook for Mac 2016, iPhone, etc. A little note: before deleting every Calendar item, I did an .OLM export. Unfortunately when I restore it back, it was missing a lot of appointment. I strongly suggest before the deletion, to export them one by one as .ICS files and or manually write them down somewhere. My best guess is that somewhere in the Calendar Exchange database there were a corrupted item, infact the OLM export-import will not work properly. I hope it helps Cheers