My iMac freezes on adding calendar events
QAfter I upgraded to Sierra, the Calendar app on my iMac started to freeze whenever I added a new event. I share this calendar over iCloud with my two other Macs, which don’t suffer the same problem. Is this an iCloud or Calendar fault?
AAlthough this could be caused by a damaged calendar on your Mac, it’s most likely to be an iCloud connectivity problem. On your affected iMac, turn Calendar sharing off in System Prefs’ iCloud pane, leave your Mac an hour or so, and check whether any calendars have populated the ~/Library/Calendar folder. If they have, ensure that they’re fully backed up, then move them to another folder – in Documents, say.
Then turn Calendars back on in the iCloud pane, wait until they’re fully restored, switch to the Calendar app and go to Calendar > Preferences > Accounts, Select your normal iCloud account on the left and change the Refresh Calendars pop-up menu to read ‘Every 15 minutes’. Close the dialog and, after a few minutes, try creating a new event.
If that has fixed the problem, as it should, you can try switching the Refresh Calendars setting back to Push if you wish, but some people find it’s best left set to one of the fixed periods instead. A similar approach can also fix some issues with the Contacts app, too.