Open both copies on a computer and check the calendar name on each event. If they belong to different calendars, uncheck the calendar that received the import in the sidebar and see which events disappear. If both copies are on the same calendar, identify the imported entry before deleting it.
01Identify the copy to keep
Section linkCompare the calendars, guests, and meeting links on both events. Google Calendar does not carry over guests or conference data when it imports events, so an entry missing those details may be the import. If you temporarily hide an import calendar, check a few dates to make sure the calendar you keep still shows the events you need.
02Delete only events you can identify
Section linkIf the unwanted copy is mixed into a calendar you use, open the specific event before choosing Delete. Deleting an event you own removes it from invitees’ calendars too. Removing an invitation can send the organizer a decline. For a repeating event you own, choose This event when you only intend to remove that occurrence. Google warns that This and following events bypasses the trash.
03Give the next import its own calendar
Section linkIn Google Calendar on the web, create a new calendar and select it as the destination under Settings → Import & export. The primary calendar is the default if you leave the selection as is. Check a few dates after importing. If a second click reports Processed zero events, look for the events in the destination before trying again. Google says the first click may already have imported the file.