iCloud Shared Calendars not syncing after 15.3.1 update

Hi all,

I had the same issue. My wife's calendar, which she shares with me, suddenly stopped syncing to my machines and devices. In fact, on one device, it would show some appointments and on others nothing. I, too, have spoken with all Apple Support levels, and I have uploaded the diagnostic files to Apple's engineers. I am expecting a callback tomorrow (Sunday) morning. However, I could not let it rest as it was bothering me. So, I think I have finally found a solution—at least one that is working now.

I will not go through all the troubleshooting steps; instead, this is the way; as of this writing, I fixed the issue. First, let me explain the hardware and setup. It is important to note that icloud.com always showed the correct information; the devices and machines weren't syncing.

Wife's System

—iMac M1

—iPhone 13 Pro

—iPad Pro (latest gen)

My Setup

—MacBook Pro M1 Max

—iMac Pro (Intel, of course)

—iPhone 13 Pro Max

—iPad Pro (latest gen)

First, I backed up my wife's shared calendar. Changed the name—disabled iCloud Sync on her machine. I generated a local calendar. I imported the local calendar into a new iCloud calendar.

I then disabled the calendar sync on all my machines and devices. I did a hard reset of my iPhone and iPad and rebooted both machines.

I then reshared her new iCloud calendar with me and accepted the invitation through iCloud.com. Shared calendars repopulated on iCloud.com just fine. On my MacBook Pro M1 MAX, I then enabled iCloud Sync again. It took a couple of minutes, but poof. All items now showed from her new shared calendar. I let it sit for a while and created tests back and forth; everything was fine.

I then enabled calendar sync on my iPhone 13 Pro Max, and poof, everything synced. I again tested creating and deleting events from both sides on her machine and my MacBook and iPhone.

Her iPhone and iPad never had an issue; it was only on my end since she shared the calendar with me. Now, I want to leave it like this for the time being to make sure nothing goes wonky again, but at least it's working on my laptop and iPhone.

It seems I've isolated it to either my iPad or iMac Pro. I have the feeling it is with my iPad, so I will later today enable calendar sync on the iMac Pro. If all goes well for a while, I most likely will format the iPad and start from scratch on the iPad as the last thing I want to do is go through this process again.

Please note: All devices and computers are and were completely up-to-date when the issue occurred, and it seemed to have happened when I updated everything.

I hope this helps, and I will keep you posted.

Hello wsscott,

It sounds like you're having trouble syncing your calendars. Check out both the "Things to check first" and "iOS 13 and iPadOS or later" sections of this article for troubleshooting suggestions: If your iCloud Contacts, Calendars, or Reminders won’t sync

Also, since you mentioned this began with the iOS 15.3.1 update, back up your iPhone; then update to iOS 15.4: Update your iPhone, iPad, or iPod touch

Take care.

HI,

Yes, it is still working on all devices and machines (hard knock on wood). The backup I did before anything was from my wife's machine since she didn't have any issues as she was the creator of the calendar that was shared with everyone else. We didn't lose any data, all data/appointments were restored to the point in time of the backup.

I only deleted the old calendar that was originally shared from my wife's machine to clear the system--iCloud--of any potential confusion with calendar ID on iCloud.

Not to confuse matters, but restoring calendar backups from iCould did nothing. This was a local backup from the machine sharing the calendar. Also, when backing up the calendar in question, make sure to use the "Export" option on the selected calendar and not the "Archive" option.

Hope this helps.

I had the same thing happen. I didn’t want to do all that stuff from the other answers, so I was going to just deal with it…then…I got bored and tried something. Simply entered a new event in the problem calendar (the one not syncing). While I was entering the event, I saw in the background all the events populating. So maybe that just gave it a kickstart. Note - when I started to create a new event, it had another calendar (not the problem / not-syncing one) selected. As soon as I changed that everything worked great.

My workaround was sort of the same but was fewer steps because it was a subscribed calendar. It was only not syncing on my iPhone but was syncing on my other devices. I deleted and added back the same calendar, and so far it's syncing and updating.

Thanks for replying, wsscott, and that additional info, it really helps! Since you are still having an issue with this, please contact Apple directly for further assistance:

Get Support 

Have a great day and thanks for using the Apple Support Communities!

Hi wsscott, I agree, my process is laborious, to say the least. So far so good from my end, but that's what worked for me. I tried sharing her calendar with me both via my mobile number and email. Email is what worked, but again, I can't remember at which point in the process I tried to share it via a mobile number. I rarely call tech support, maybe twice in over a decade, but I have to agree, reaching their highest level of support was disappointing, to say the least; however, they were very kind and followed up every time they said they would.

Looks like all the Share Links for my Public Calendars changed in the last few weeks. I had them set up with QR codes and started having people come to me with problems. Old links started with webcal://p42 and the new ones are webcal://p56. But it seems like the links auto updated for people who were already subscribed? New people would get an "unsecure, yada, yada" popup.

WTH. 🤷‍♀️

I am having the same problem. I am unsure when it started, but I’m running iOS 15.4, and one subscribed calendar stopped syncing. That same calendar syncs fine on my iPad, also on 15.4. Refreshing the calendars does nothing.

I just tried disabling and enabling iCloud sync for Calendars, hoping it would refresh the problematic calendar. Instead, no events are syncing from that calendar. I’m just going to remove and re-subscribe to it.

I am having a simlar issue. I have several icloud calendar accounts that sync with a dakboard to display our family schedules in one place. This update has made the public link unrecognizable with dakboard. They are suggesting turn off public sharing and so that icloud will issue and updated public link, but I cannot get it published to a new public link. Any ideas? I have 5 calendars syncing, only two are having issues.