Calendar slow/unresponsive after Mountain Lion update

MetallicAsh,

Try removing the com.apple.iCal.plist file from your Macintosh HD/Users/yourusername/Library/Preferences Folder. To find that Library folder, use Finder>Go Menu>Depress the "Option" key>Library. Drag the .plist file to your desktop, and log out/in or restart.

Then go to your Macintosh HD/Users/yourusername/Library/Calendars Folder and remove any files with "Cache" as a part of the file name. Use the same method as listed above to get to the correct Library Folder. Log out/in, or restart and check Calendars for functionality.

MetallicAsh,

Backup your calendars, then delete {-} and re-add {+} your iCloud account.

I'm experiencing the very same issue, already tried readding the caldav and icloud account

Add me to the list...

On 10.7, my iCal was very fast and responsive. Now, with 10.8, making any change to an entry (add, change, delete) makes Calendar unresponsive for about 3-5 seconds (spinning beachball).

Pretty annoying since it's an important tool that I use frequently daily.

Hi MetallicAsh and others,

For those of you having a Calendar performance issue, have you noticed if you got the following message in Console? The message I get is:

CalendarAgent[7459]: Property list invalid for format: 100 (property lists cannot contain objects of type 'CFSet')

I get this error after any change to my calendar events stored in iCloud.

I don't get the error message for Exchange calendar events, but I still have the delay. During this delay, Calendar tops the CPU at 100% for about 3-5 seconds.

Any similar or disimilar behaviours on your side? Or have you been able to solve it?

Thanks!

Hi Bernz,

yes I do and I have. I must admit that sinds ML several aspects tend to slow down or stop. I have a late '11 MBP with 8gb, and performance wise SL was a lot faster with those specs. Caldendar acts up. I also have issues with Contacts. I also had several crashes where I had to do the 5 sec. stop. In the console log? MDS error. CGSReleaseWindowList: called with 10 invalid window(s), etc.

Thanks for the suggestion ...

I dragged this file onto my desktop from username/library/prefeerences:

com.apple.iCal.plist

I also dragged these files onto my desktop from username/library/calendars:

Email Cache.plist

Calendar Cache

THE PROBLEM IS GONE!!!!

I dragged this file onto my desktop from username/library/prefeerences:

com.apple.iCal.plist

I also dragged these files onto my desktop from username/library/calendars:

Email Cache.plist

Calendar Cache

This worked for me. Thanks for the suggestion.

I shutdown iCal, logged off, and then moved the files. Then I did a complete re-boot before starting iCal again.

When I first restarted iCal it went thrrough the "Upgrading Calendars" process again.

Sorry it did not work for you.

It might look like a huge pain, but I finally resolved my problem this way:

I created a new user, migrated all my data over (except the iCloud data), activated iCloud and ever since, I've had a super-fast calendar.

My guess is that there is a cache hidden somewhere on the system that the new engine has trouble parsing... By creating a new user and connecting to iCloud, you get a brand-new cache and *hopefully* great performances.

To test it out:

• create a new user on you Mac
• log in and activate iCloud
• do a few tests in your calendar; you should find it zippy-fast...!

Hope this might help you!

I know this sounds weird, but I did get some lag on my new account from time to time. After a few weeks, it became fast.

...

I suspect that the iCloud data center has something to do with it, because I didn't change anything afterwards and the performance changed...

If someone has insight in this, maybe it could shed some light on the problem.

Bottom line: I migrated my account and since then, I get instant results with my iCloud calendar. I sure hope this can help getting your fix.