Yosemite Calendar - Outlook/Exchange calendar events keep updating and sending out invitations to participants

It's good to know I'm not alone. 🙂 I've also submitted feedback.

I have the same issue and been noticing it for a while. I have escalated this to our Enterprise Support with Apple and I will keep everyone posted if we get a fix.

+1, a pain!

This is a Calendar issue, but it is also tied in with Mail. I have several users with MacBook Pro's and iMacs. Nobody on Mavericks is having this issue but the two users I upgraded to Yosemite are having this issue. (we are using Exchange V2010)

What we noticed is that when accepting or rejecting invitations, the Yosemite user replies get stuck in Drafts. We have to open the draft and manually send the email to settle the issue. Could be that your version is sending the drafts but not quite confirming 'sent' and does it over and over?

For the record, I spent almost two hours with Apple Care demonstrating this problem and its relationship to a message that says it is "unable to save the message" and offers to try again, revert to server or ignore. No answer resolves the issue. The user boards on these issues have more answers than Apple Care is able to provide.

This is the best repair I've found to date:

Open System Preferences>Internet Accounts, select the Exchange account and turn off Calendar. Then, go to Calendar>Preferences and delete the exchange account. Next. In the Finder, hold down the option key, click Go and Scroll down to Library. There, navigate to the Calendars Folder. Delete Calendar Cache and all the folders labeled with long strings of numbers and letters. Click on the Pending Events Folder and, again, delete all the folders labeled with long strings of numbers and letters.

Then, go back to System Preferences>Internet Accounts, select the Exchange account and click to turn the Calendar back on. Restart your computer.

That seems to clear out the problem. Until iCal creates it again...

+1 same here! Just turned on ignore alerts and getting ready to re-sync Outlook for alerting :-( Can't wait for this to be fixed!

The OS X 10.10.3 update seems to have fixed this! I can now press either "Close" or "Snooze" on a Notification Center Alert and neither action causes the event to be resent to participants. Yea!

We use Exchange Online with Apple Mail and iCal in a predominantly 10.8.5 environment but starting the upgrade process to 10.10.2 (which has been extremely painful)

One of the wonderful issues we found was the repeated invites constantly sending to all invitees and I spent a considerable amount of time banging my head against a brick wall.

Then yesterday I FINALLY found out what is causing the problem....

If the organiser of the event receives an acceptance/decline/etc to a meeting they've setup, then receives a notification within iCal to which they click OK on, it will send out an update to everyone invited to the event.

So it's the clicking OK which triggers the 'update', I guess because on some level iCal sees this as a modification to the event, and any modifications would usually prompt you to confirm whether you want to revert or send changes, but as there is no prompt it automatically triggers an update to event participants. This isn't an issue on 10.8 machines. Not sure about 10.9 as we skipped that OS.

Sooo... Next stage would be to vigorously test this then submit all the results to Apple in the hope that they develop a fix for this.. If not looks like we'll be switching to Outlook......

Fun times.

Same issue, I tried mtb1nary's suggestions....let's hope it works

It's also worth noting that the invites getting stuck in the Drafts folder is a separate issue. And seems to be generated when you accept an invite via iCal rather than responding to the Mail invitation.

Deleting the profile and caches won't fix the issue of organisers sending repeat messages. This'll be down to Apple to provide a software fix for.

I believe Apple has now fixed this. The OS X 10.10.3 update corrects the issue of Snooze/Close on Notification Alerts sending spurious meeting updates to participants.

I'm on the latest rev of 10.10.3 and still see the issue. It didn't happen with 1 meeting (Single invitee) but did happen on another. (Multiple invitees)

I have not seen an issue on 10.10.3 beta and production for about 2 weeks now.

I still see the issue on the latest version of 10.10.3. Every time I get a reminder for a meeting I created in calendar, all other invitees get the invitation again through Exchange.

Still happening with my Macs too.

It just happened to me again so still not fixed. I just reported back to Apple Enterprise Support. This *****!