I have an early 2013 Mac Pro running Big Sur 11.6.5 and an iPhone SE Version 15.4;. This morning, all of my calendar events on my Mac Pro have disappeared, but they are still on my iPhone. Restarting, turning iCloud Calendar off and back on, neither seems to help. If I re-enter the events on my Mac Pro, they show up on my iPhone SE as duplicates! This is crazy!
Mac Pro, macOS 11.6
See the articles If your iCloud Contacts, Calendars, or Reminders won’t sync - Apple Support
Sync contacts and calendars between your Mac and iPhone or iPad - Apple Support (IN)
Note : you mentioned - . If I re-enter the events on my Mac Pro, they show up on my iPhone SE as duplicates! This is crazy!
Once an event is created Add, modify or delete events in Calendar on Mac - Apple Support its completed , when you create a new event it will be different from the previous one ( however the new calendar event will also sync , but it will not be identical with old calendar event so it will not be treated as duplicate event .
In case if you deliberately create a duplicate event then the scenario will be different Set up or delete a repeating event in Calendar on Mac - Apple Support
See the articles If your iCloud Contacts, Calendars, or Reminders won’t sync - Apple Support
Sync contacts and calendars between your Mac and iPhone or iPad - Apple Support (IN)
Note : you mentioned - . If I re-enter the events on my Mac Pro, they show up on my iPhone SE as duplicates! This is crazy!
Once an event is created Add, modify or delete events in Calendar on Mac - Apple Support its completed , when you create a new event it will be different from the previous one ( however the new calendar event will also sync , but it will not be identical with old calendar event so it will not be treated as duplicate event .
In case if you deliberately create a duplicate event then the scenario will be different Set up or delete a repeating event in Calendar on Mac - Apple Support
After reading the suggested articles, I brought up my phone and went into iCloud settings. I turned Calendar off, waited a bit, turned it back on, and mirabile dictu! All fixed. Thanks.
My calendar events have disappeared on Mac Pro in Big Sur, but still on iPhone SE
