[Update: Workaround] Apple Calendar app on iOS 15.1 not working/unresponsive, lagging or not syncing for some users

New updates are being added at the bottom of this story…….

Original story (published on November 11, 2021) follows:

It seems that the Apple Calendar app is having some issues after the update to iOS 15. Also, it seems that the problems persist on iOS 15.1 update.

Users report that, even after updating their devices to the latest iOS 15.1, the Apple Calendar app still not working properly and becomes laggy/unresponsive.

The issues reportedly started on iOS 15

Apple Calendar app performance issues would have started with the arrival of iOS 15 (1, 2).

Users complained that the sync function was not working properly. Also, various error messages appeared.

Summary: Owner of a shared calendar updated iPhone 12 Pro Max to iOS 15, now I am unable to see events associated with a shared calendar on my apple devices (MacBook Air (Big Sur), iPhone X (iOS 15)).

Additional Info:

I occasionally receive an error message in the calendar app:
“The server responded with an error.
The request for account ‘iCloud’ Failed.
The server responded with ‘500’ to operation CalDAVAccountRefreshQueueableOperation”

I appreciate any help from the community! Thanks in advance

Apple Calendar app on latest iOS 15.1 could be even worse

With the update to iOS 15.1, affected users expected the calendar issue to be resolved. However, it seems that not only is it still there, but it would have gotten worse (1, 2, 3, 4, 5, 6).

Has anybody else noticed really terrible performance regressions in the Calendar app both for macOS 12.0.1 (but not 11.6) and iOS/iPadOS 15.1 (but not 15.0.1)? On macOS all operations produce the spinning lollypop for several minutes. On iOS, it’s only list view.

When swiping between days, data often shows up as stale (events on the wrong day, or events at the “right” time but with wrong title).

Keeping the same day view open for up to 10 seconds seems to correct the issue (temporarily). This appears to be some kind of caching bug.

(This was *not* an issue in 15.0, 15.0.1 or 15.0.2. I have one MS Exchange calendar and three Google calendars.)

Now, according to users, the Apple Calendar app on iOS 15.1 is also laggy and unresponsive. Added to this are the problems with the sync feature.

macOS Monterey users reportedly affected too

Not only iOS devices are having issues with the Apple Calendar app after recent updates. Some reports indicate that macOS devices would also be affected.


For some macOS users, the app even crashes constantly, severely interfering with its use:


At the moment, Apple has not commented on this matter. Therefore, it is not known if they are already aware or if they are working to fix it.

If there is any new development in this regard in the coming days, we will update this article, so stay tuned. You can also check the bug/issue tracker dedicated to iOS 15 to stay informed.

Update 1 (November 12)

06:15 pm (IST): An individual claims to have a workaround that helped them fix the issue. Check it out below:

FIXED! I contacted support after trying the fixes here. This is what worked

go to your calendar

delete (yep scary)

go to app store

search “calendars”

select the App that has “productivity” under the name.


all appointments came immediately back on (Source)

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Jean Leon

A tech enthusiast since ever. I like to always be up to date on the latest news in the industry and write about it.