CalendarAgent hogs CPU to 100% every time I get network connection The CalendarAgent service takes all my CPU, every time I get a network connection.
This is really annoying in many situations (one example: closing the lid for 2 minutes, change train and open it again) and slows down everything.

I already tried many solution:


reset the calendars
clear the cache files
change configs for the accounts
renice the CalendarAgent process
set ALL my accounts to manual refresh (Command + R)


The service doesn't care; if it's active it will hog the CPU.
Only alternative is to disable the service; but, what a surprise, the Calendar app won't work anymore and crash.

I have calendars in sync with iCloud, Exchange, Google.

I'm struggling with this issue and would really like to take control back on this annoying process.
I am fine with having to refresh manually the calendars but at least decide when to hog the CPU with updates.

How can I solve this?

OSX: El Capitan
I had the same problem with El Capitan, High Sierra, and now Mojave (seems to have worsened).
For me the removing the google delegation seems to have solved the issue:
How can I diagnose or fix the CalendarAgent occupying a whole CPU on Mountain Lion?