HT202158 Ical crawling

Question

I have been using Ical on my macbook air 2011 and ical for over 10 years before ical was even on the cloud.  I was able to publish and employees were able to access our calendars for years without glitches.  Despite deleting years of data and having to delete each entry manually talk about carpal calendar iCal is still slow.  Multiple duplicates in some cases up to 10 per entry and the older the calendar the more duplicates.
I am definitely using less data than last year but iCal is still crawling.
Any suggestions is Ical really not meant for regular long term use?
Should I open a new account and start over?
Should I keep deleting?
Any way to mass delete duplicates or to simply say archive and delete calendars over 5 years old?

Answer 1

Are the calendars hers? If so, are they published somewhere? Are they someone else's that she has suscribed to? Are they synchronised anywhere? Are they very large (as in many events, some of doubtful historical interest)? Are there many repeating events?
These are things that will slow down iCal. If none of them apply it would be worth turning off all calendars excep one, then quit and restart. If iCal then behaves normally, repeat with the next until you find one that causes the slow-down - bad data in a calendar can also affect performance. Alternatively, export all the calendars in turn, then delete them all and re-import them one at a time.
AK