iOS 15.1 Calendar app is laggy and unreliable

It looks like a solution will be rolled out in 15.2 - released imminently

This release also includes bug fixes for your iPhone:

·        

Siri may not respond while VoiceOver is running and

iPhone is locked

·        

ProRAW photos may appear overexposed when viewing

in third-party photo editing apps

·        

HomeKit scenes that include a garage door may not

run from CarPlay when your iPhone is locked

·        

CarPlay may not update Now Playing information for

certain apps

·        

Video streaming apps may not load content on iPhone

13 models

·     

Calendar

events may appear on the wrong day for Microsoft Exchange users

from

https://www.macworld.com/article/547488/ios-15-2-features-release-how-to-install.html

I am having the same issue, but my issue is due to my work Exchange account. Tested removing all accounts:

1 Outlook (that has 2 iCal subscribed)

1 Exchange work

When I added all except Exchange back it worked just as before 15.1. When adding the Exchange account back (after running without it for a while) the issues started happening again.

My IT department originally demanded everyone update their iPhones to 15.

I did as I was told by the deadline and discovered this exchange issue.

I let my IT team know and they said I was the only one having the issue.

yesterday they sent this round:

Please note that Apple have acknowledged an issue between its latest version of the operating system 15.1 and its compatibility with Microsoft’s Outlook calendar. Please do not upgrade to this version at this point – the last approved and stable version was 15.02 - we will advise when Apple have released a newer version that works with Outlook.

Microsoft recommend that you download the Outlook app from the app store and use the outlook application instead of the default Mail application that comes with the Apple operating system on an iPhone.

I talked to someone at Apple Support. Here’s the fix that worked for me. Temporarily turn off the calendar in your microsoft exchange account. Go to home screen and delete the calendar app. Go to the Apple App Store, then search and download the calendar app again. Go back to the exchange account and enable the calendar again. All my meetings showed up again.

Yes, it’s been a huge disappointment. I talked to Apple support today and they instructed that I should delete the Apple Calendar app from the home page, go to the App store and download it again. I first went to Settings and disabled the Calendar downloads from the Microsoft Exchange server, then after downloading the Apple calendar, I re-enabled the exchange server calendar. While not perfect, my appointments now show up and there’s a slight lag when navigating from one day to the other. Closing and reopening the “new” app fixes temporary freezing. But it’s MUCH better than it had been heretofore, this.

Same issue for me, iPhone SE 2nd generation, about 18 months old, on 15.1, laggy and freezing on Calendar app for a couple weeks now. Spent 45 minutes chatting with Apple Support on Saturday, they couldn't see anything wrong. Spent 3 hours at Apple store on Saturday, they initially diagnosed a faulty screen (keyboard was glitchy at times too), so they replaced that, but Calendar freezing and lagging persisted, so we did a full factory reset and I started to install everything back as if it were a new phone. Calendar app was working fine through all this, but I added my work Exchange account this morning and 10 minutes later the Calendar was lagging and freezing again. I then added the MS Outlook app and now direct my work email and calendar through there, and took them off the Apple Calendar, and both apps work normally now with no lagging or freezing. Frustrating to have to add another app to fix Apple's problem.

Lots of places quoting Apple

saying

This release also includes bug fixes for your iPhone:

• ...
• Calendar events may appear on the wrong day for Microsoft Exchange users

e.g.

https://www.macworld.com/article/547488/ios-15-2-features-release-how-to-install.html

The update has gone to 2nd release candidate so should be out to the public maybe as early as tomorrow

Solved in iOS 15.2.

using iOS since iPhone 4, must say that it’s the first time that I found an issues with the core business apps at iOS (mail, calendar… )

one thing I did was to delete the calendar app and install it again ( ya, scary… but works)

Fixed with 15.2!!

Its fixed in 15.2 released today

Same here with an exchange account. As soon as I remove the company exchange account, it works fine (iCloud only in calendar).

Removing and re-adding exchange account does not help.

ios 15.1

iphone 13 pro

Same to me on 15.1.

The problem is persisting if there is any Exchange calendar in mail accounts.

When I removed Exchange account from accounts on my iPhone, the calendar worked fine - no lagging. Not good due the Exchange is my work mail

Putting the phone in landscape orientation BEFORE you open calendar (per another user's suggestion) seems to work for me. Also, I'm using the Outlook app for accessing my calendar--not ideal, but at least I know when/where I gotta be until it gets fixed.

I had this problem on my iPhone (Exchange extremely slow, dates showing wrong events, etc.). So far it looks like I have mostly fixed it by disabling the "iCloud Private Relay" on my Wi-Fi connection. It loads and updates faster.

Here are the steps.

• Open Settings
• Select "Wi-Fi"
• Click on the ( i ) info circle for the wi-fi network to which you are connected
• Scroll down and UNSELECT the "iCloud Private Relay."

This lessens the problem, but it means disabling the new security enhancement.

This helped a lot for me. I suspect there is still something going on with the App itself.

I had the lagging o365 calendar issue for weeks 🤬but today I changed the no of days to sync emails on the o365 account in settings to 1 day - this changed the lagging and the performance is almost back to normal