How do I undo an import into macOS calendar? I imported an iCalendar (.ics) file into macOS Calendar. Because I expected the file to only contain a handful of events, I chose to add the events to an existing calendar rather than create a new one. However, the file turned out to contain hundreds or thousands of events, most of which were not relevant to me and which I don't want spamming my calendar.

I tried to undo the import immediately after it happened, but undo was not available. I tried manually deleting some of the events, which works for some of them, but many others have other invitees and Calendar says it will notify them when I delete the event which I want to avoid as it would mean sending many notifications. I don't want to delete the calendar to which I added the events, as it already contained a lot of events that I don't want to lose and that would be a lot of work to note down and recreate.

Is there any way I can bulk remove these events without sending a bunch of notifications? I'm willing to use third-party software if necessary.

Edited to add: Most/all of the invitees on these events are long_string_of_mixed_alphanumerics@group.calendar.google.com addresses, so I assume the emails would be sent to some sort of group of subscribers or members on the Google Calendar from which the events were exported.

If I try to move one of the offending events to another calendar, I get a message:


  You're about to send an invitation for "event_name".
  
  Do you want to send "event_name" now, continue editing the event or revert the changes?


The options are Revert, Edit, or Send.
It sounds like your calendar event was generated from Google Calendar as an event which 'repeats itself' a number of times. If that is the case, and if you have imported this event in a calendar which you have linked to a Google account, you should be able to open it from Google Calendar and remove the event from there, including all the recurrencies of the event. When you do so, you can choose not to notify others of these deletions.