iOS 15.1 Calendar app is laggy and unreliable

One thing that I have figured out is that if you toggle off the calendar for the Exchange account on your iPhone, it fixes the issue if you have that same Exchange account on an iPad and/or Mac. In other words, those seem to operate just fine if your iPhone Exchange account is turned off. What is strange is that ir doesn't work the other way around. Thus, I surmise it has something to do with the Exchange account on the iPhone.

jpetrosoc wrote:

One thing that I have figured out is that if you toggle off the calendar for the Exchange account on your iPhone, it fixes the issue if you have that same Exchange account on an iPad and/or Mac. In other words, those seem to operate just fine if your iPhone Exchange account is turned off. What is strange is that ir doesn't work the other way around. Thus, I surmise it has something to do with the Exchange account on the iPhone.

Great that you've found a solution. But, as a data point, I have an Exchange calendar enabled on my phone and do not have this problem.

I just mean people to monitor these forums, and pass on complaints as well.

I understand how it works here. I’ve been helping people since February of this year.

I’m 13, most other people here who have dedicated many hours and made it to level 10, or whatever probably know more than me. Like you for example, obviously know more about this, being at level 10 with 123,434 points. I admire the people like you, who know a lot, and are able to provide more information for the people who reply to problems on here. So I devote a couple hours a day just to learning about apple products, and some other products too, because sometimes people have issues with android, one ui, pc or whatever.

I think at this point, I will just back out of this argument before we start world war 3. (I’m not blaming you, it’s technically me who kept it going, and I do apologize for that.

PROBLEM FIXED FOR ME: As per my initial post, after deleting a recurring zoom meeting invitation from my calendar, my calendar has and continues to work as it did prior to installing the latest upgrade. I have no idea why deleting this recurreing meeting with an embedded zoom link would have any effect, I'm just happy that my calendar is no longer laggy.

My calendar is littered wall to wall with single and recurring Zoom, Microsoft Teams, WebEx, and GoToMeetings. None of which can be deleted, I need them. No quick fix for me. I depended on this app to tie together my Exchange Online and 3 different gmail accounts. Real pain and inconvenience this bug is. Landscape workaround is all I got, outside of just waiting till I sit down to my laptops to see what my day consists of. Not really a great option since I also track my kids piano practices, bowling, doctor appointments, contractors coming to the house, etc. Track and organize everything I do with this app… or did rather.

I too am experiencing this issue after updating my iPhone XS to iOS 15.

I assumed it maybe be my old phone struggling to keep up but it pains me to say that after receiving my new iPhone 13 Pro, the issue still persists

I have one personal and one work outlook account plus a share calendar

Hope this is fixed ASAP as it is incredibly annoying

Sorry you went to all that trouble. Your calendar will likely start begin laggy and unresponsive in another day or two. None of the "fixes" posted here keep the issue from coming back. The software has a bug and there is no permanent workaround or fix other than the bug fix we are all waiting for. I've tried the stuff folks have posted here as well and none of it seems to be permanent.

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.

Yes I got too excited too soon - same has happened to me. I have switched on and rebooted phone and at the moment ....... it might be ok - I am getting a slight lag but within a second or 2 it is correct

I have the same problem and it is really frustrating, access to calendar has gone from easy to impossible since updates, just not sure which update has caused this. I use iCal and

. 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.)

I have been onto Apple Support. They tried to help me but I pointed out I was one of millions and so not my issue but a basic IoS problem. they confirm that a team is on this working with Google and MSFt to try to resolve it.

Sadly we have to wait.

Try rebooting phone! 

For iPhone X onwards press the volume up button then immediately press the down then hold the off button until the screen goes dark and then you see the apple Logo!

If before the iPhone X then hold the off and home button till it turns off and the apple logo appears!

This issue is fixed in iOS 15.2. Here’s an excerpt from the release notes: “This release also includes bug fixes for your iPhone: Calendar events may appear on the wrong day for Microsoft Exchange users”

I’m now on 15.1.1 and same issue. Seems to be an issue with swiping between days. I don’t have any exchange accounts on mine, just a few Google, and iCloud and hotmail. I’ve found that force closing the app and then reopening seems to work immediately (without having to wait and wait for the app to update).

Super unreliable and a huge inconvenience. I’m mostly switched to Google Calendar now so I can follow my work schedule, but that still doesn’t show me my family iCloud calendar

Ahhh Apple, always up for a bit of corporate gaslighting. They obviously knew they had a problem, but rather than acknowledge it, they had their genius' continue to waste peoples time by restoring (or worse resetting and starting fresh) their devices. I'd be pretty annoyed if I was one of those people.