Calendar very slow with macOS Monterey

I don’t think this is entirely related to Exchange calendars. I tried disabling my Exchange account but it did not solve the issue. I do have a number of subscribed calendars (iCal) and believe the issue may be related to these as well. As I pointed out, this appeared in macOS Monterey starting with beta 6 and carried all the way through to the final release. I reported it to Apple with every beta since then and received zero response. I sent them screen recordings and everything. The issue did not exist in iOS/iPadOS 15.0 but appeared with the release of 15.1. This is Apple’s problem, no one else’s. As another user pointed out above, it only happens in Monterey/iOS15 and not in the previous version of the operating systems and does not happen in any calendar apps but the Apple’s stock app.

[Edited by Moderator]

@me definitely not the issue here. I have always used iCloud. And as others have pointed out, it appears to be related to accounts, which worked fine prior to the upgrade, that have a lot of events associated with them, such as work based accounts on Google, Microsoft or any other services.

I have exactly the same issue as Mark. However I am starting to doubt that the issue is MS Exchange, I am rather asking myself, whether it could be the difference between the "old" iCloud and the new iCloud+.

Why?

I still have an MBP from 2019 running on BigSur 11.6.1. - no issues at all.

I also have an iPad Pro from 2019 that is running on iOS 15.0.2 - no issues at all.

Then I have upgraded three MBP's (one from 2019 with Intel i9, two brand new with the M1Max-Chip) - all three have the issues described by Mark above.

I also have an iPad pro from 2020 that I upgraded to iOS 15.1. - it is now showing the same issues as well.

On all machines that have the issue with the slow calendar, it only happens when using the Apple Calendar (MacBook as well as iPad). When using external calendars such as Fantastical and/or MiCal everything is fast and smooth as ever. By the way: No big differences whether I run MS Exchange or switch it off.

Could it be iCloud+ ?

I notice that the problem persists even when my Mac is not connected to the internet, when Calendar is using only its local copy. Hence doesn't seem to be an issue with connecting to various cloud databases. One can hope that someone at Apple is aware of the problem and is working to fix it, but I have my doubts.

Confirm this issue. I think this bug is connected with new "Join to conference" button.

No, the problem is definitely with the Apple calendar:

1. 1. 1. It only happens on Monterey, and doesn't happen on Catalina / Big Sur
      2. It doesn't happen on any other calendar app

Hi,

same issue on my side. But I didn't use exchange, I use owncloud caldav calendar. If I uncheck it the callendar work fine. But I have to use this Cloud calendar for work.

pls help us quick.

I have the same issue with Apple Calendar and Exchange slow syncing (at least it seems that's what's happening) since upgrading to Monterey. Apple Calendar takes ages to launch and simply switching from one week's view to the next week takes over 5 seconds to load in the events. Switch back to the week you just left, it starts blank, then takes 5 seconds to re-load the events.

I have the Fantastical Calendar app on my Mac too, it also syncs with Exchange and has NONE of the issues Apple Calendar is showing, but I prefer Apple's Calendar to Fantastical because it's normally simple and quick to add and edit events. I'm hoping it will be fixed soon.

I have the same problem. I think it's the client or perhaps the way it interfaces with other servers, because I don't have Exchange calendars but use Google's calendars and still have this really annoying delay. It's really not usable any more, hope Apple can fix it else I'd probably move away from using Calendar on MacOS.

Same here. I got a call with a senior tech at Apple and after several tries, they didn't have a clue of what is going on.

I don't have any Exchange calendar but the same spinning wheels and a very annoying slowdown.

Have exactly the same issue after installing maCOS Monterey. Exchange account of iCal is painfully slow and just doesn't work. Similar issues with iOS devices after latest update too.

Real problem and hope Apple sorts this out. They keep having issues with Exchange.

Similar issue since Monterey installation. However, in my specific case, I'm not using exchange, juste icloud calendar. What is weird is that some calendar meeting are smooth to open and edit, while other are extremly slow. @Apple, please help us solve this very annoyng issue on Ical.

When I'm viewing events for one week, then change to a different week, there's a ~8-10 second delay before content on that new week appears, with the cursor spinning during this time. (Almost all of my events are from an Exchange calendar.)

Same problem as everyone else: calendar wheel spins & spins. None of the bad add-ins that Old Toad listed. Tried booting in Safe Mode per suggestion, and Calendar was even worse: Clicking on one event hijacked the entire machine -- couldn't tab out to another app, couldn't get to the apple to force-quit; fan spun up to highest possible speed. Took 2-3 minutes to have *any* interaction with the machine. And still can't use calendar. This pretty much makes Monterey unusable, as far as I can tell.

I am adding some configuration information here: I have no issue on my iPad with calendar (didn't go 15.1 with it yet). But my iPhone (15.1) and MacBook Pro (Monterey) are very unhappy. For now, not upgrading, if viable, is the best way to avoid this. Alternatively, don't upgrade at least one devic.