A runaway, memory-eating process in Mac OS X Mountain Lion that I’ve whined about on Twitter and in last weekend’s USAToday.com column seems to have returned to sanity.
At first, this CalendarAgent program had been a mild-mannered citizen on both my MacBook Air and on my older iMac. But a day or two after Discovery News posted my generally positive review of Mountain Lion, the iMac started locking up as CalendarAgent devoured as much as three to four gigabytes until I force-quit it with OS X’s Activity Monitor app.
The problem went away long enough for a cautious endorsement of Activity Monitor in Sunday’s USAT piece, but then it resumed. After a few days of getting bored with killing off this process two or three times an hour, I was trying to remember how to yank its execute privileges when I thought to check the Console app.
The repeated errors listed in this troubleshooting tool indicated that CalendarAgent was choking on my wife’s shared Google Calendar feed. I’d subscribed to that in Lion’s iCal without any issues (parenthood requires a non-trivial coordination of schedules), but Mountain Lion apparently had other opinions. I deleted the subscription from ML’s Calendar app, added it back in the BusySync software I use to publish my own set of calendars to Google, and was soon treated to the welcome and overdue sight of CalendarAgent’s memory allocation dropping back to normal levels.
I still don’t know what exactly went wrong on the iMac; the MacBook Air didn’t have this problem even after I subscribed directly to my wife’s schedule in its Calendar app. Adding it under the “delegation” option for the Google account I’d already configured in that copy of Mountain Lion–but which I hadn’t set up on the iMac–didn’t result in any memory leaks either.
But if you’re tired of seeing CalendarAgent hold up your Mac, try changing how Google calendars get to the computer. Instead of adding a direct .ics subscription via Calendar’s Edit menu, subscribe to that feed in your Google Calendar, add that Google account in System Preferences’ Mail, Contacts and Calendars pane and you should see the subscription when you click Calendar’s “Calendars” button look under “Delegates.” Or revert from the delegation approach to a direct subscription. Let me know if that yields any better results.
Rob Pegoraro 
Hey Rob,
Nice write-up. Delegate calendars in particular have a long history of working poorly in iCal. This was an outstanding bug all the way up to Mountain Lion’s Developer Previews (more info here: http://support.wireload.net/entries/455889-help-some-of-my-google-calendar-exchange-calendars-don-t-show-up), but it appears as it is still having issues for some users. This appears to be particular true if you upgraded to Mountain Lion.
I was however in touch with one of our users of Blotter, and while he didn’t describe the CPU-hogging you did, he did have issues with delegate calendars in Mountain Lion. Take a look at ‘Update 2’ I posted in the blog post you linked to (http://wireload.net/2012/08/view-google-calendar-delegate-calendars-in-blotter/).
Also, as you know, simply subscribing to delegate calendars isn’t ideal, as it only provides read-only access.
Regards,
Viktor Petersson,
WireLoad
Thanks for the detailed input! The read-only access is all I need in this case (if I started editing my wife’s appointments, she might want to return the favor :).
On 2-step verification.
First, can’t get logged onto the discovery site, they don’t seem to be talking to google or facebook.
Second: James Fallows has a HOWTO up:http://www.theatlantic.com/technology/archive/2012/08/gmails-2-step-verification-some-faqs/260934/
I can’t get Google authentication to work on there either. It still accepts a Twitter identity, which is why you see my comments under my Twitter profile picture.
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Hi Rob,
I’ve just discovered your explanation here (August 8, 2012).
Maybe it’s what I’ve been hoping for… now, in June 2016 🙂
But I don’t understand it all :-((
Here’s my problem:
I switch on my MacBook Air OS 10.6.8 and after about 10 minutes—without me touching anything at all—there’s no empty space left. Swapfiles have been created and filled the 8Gb that was available on the 60Gb SSD.
So: I opened Activity Monitor. After a few minutes it became clear that iCal Helper had the biggest Real Memory and soon after that its Virtual Memory that had started at less than 236 Kb was growing in Gigas; ending up consuming all the available SSD space, about 8 Gb. Its Real Memory also grew, from about 330 Kb up to nearly 800Mb.
What to do?
Should I trash iCal?
Should I trash iCal Helper? (using Onyx I can see invisible files, but haven’t yet found iCal Helper)
What can I do?
Brian
I tried the command line version and it worked perfectly. I wonder what the repercussions are though?