Importing calendar data into Google Calendar is a common source of duplicate events. Whether you are migrating from Outlook, importing a timetable from your MIS, or syncing data from a third-party scheduling tool, import errors can leave you with two, three, or even more copies of the same event scattered across your calendar.
How calendar import duplicates happen
- Running the import twice: The most common cause. Google Calendar's import function does not detect or prevent duplicate imports — running it twice creates two copies of every event.
- Migration errors: During a migration from another calendar system, the migration tool may push events to Google Calendar that also exist from a previous import.
- Sync conflicts: When two calendar systems are connected bidirectionally and a sync event causes an event to be written twice.
- Partial imports: An import that failed halfway, followed by a retry, can leave a mixed state where some events exist once and others exist twice.
How to assess the damage
Before deciding on a fix, understand the scope:
- How many calendars are affected?
- What date range contains the duplicates?
- Are future events affected as well as past ones?
The most effective fix: clear and re-import cleanly
For most duplicate import situations, the cleanest resolution is to clear the affected calendar entirely and re-import from a single, clean source file. This is faster and more reliable than trying to identify and delete individual duplicates.
- Obtain or recreate the original clean ICS file you intended to import
- Sign into wipeaway.app and select the affected calendar
- Set a cut-off date that covers the entire date range of the duplicated events
- Review the count — it will be higher than expected because of the duplicates
- Confirm and clear all events in the affected range
- Re-import from the clean ICS file: Google Calendar → Settings → Import & Export → Import
Before clearing: confirm you have a clean, single copy of the original import file. If the ICS file itself contained duplicates, importing it again will recreate the same problem.
If only future events have duplicates
If your past events are correct but future events are duplicated, set your WipeAway cut-off date to today and clear only future events, then re-import just the future date range from a clean source.