ICS Import Created Duplicate Events – How to Clean It Up

If you imported an .ics file and now your calendar is full of duplicate events, you’re not alone. This is a common headache for event planners, coordinators, and anyone who imports schedules from different tools.

This page explains:

• Why imports sometimes create duplicates
• How to clean them up
• How to avoid duplicates next time

If you want to quickly check whether the file itself is part of the problem:

1. Common reasons for duplicate events

Duplicate events usually come from one of these patterns:

• The same .ics file was imported multiple times into the same calendar.
• You subscribed to a calendar link and also imported a one‑time file containing the same events.
• The .ics file contains duplicate VEVENT entries with the same details.
• Recurring events (RRULE) are misconfigured, causing extra copies to appear.

Your calendar doesn’t always know which events are “old” vs. “new” — it just sees a list of events and adds them.

2. Quick cleanup strategies

How you clean up duplicates depends on how bad the problem is:

A) If duplicates are all in one separate calendar

Sometimes imports create a new calendar (e.g., “Imported” or the event name).

1. In Google Calendar, Outlook, or Apple Calendar, look at the calendar list.
2. If you see a separate calendar that contains only duplicates, you can:
   • Hide it, or
   • Delete that calendar entirely.

B) If duplicates are mixed into your main calendar

This is trickier because you can’t just delete the whole calendar.

Options:

• Sort events by name and manually delete obvious duplicates (works for small imports).
• If the events came from a subscription, remove the subscription and re‑import a clean file.
• Ask your IT or vendor to help clean up via tools/scripts if the volume is large.

CorrectICS can’t directly delete events from your calendar, but it can help ensure the next import doesn’t add even more duplicates.

3. Check whether the ICS file itself has duplicates

Sometimes the .ics file includes the same event more than once, or uses identifiers in a way that confuses calendar apps.

To inspect it without digging through raw text:

1. Go to /fix on CorrectICS.
2. Upload the .ics file you imported.
3. Review the issue list for:
   • Duplicate UIDs
   • Repeated events
   • Recurrence rule (RRULE) warnings

Even if the file is technically valid, the report can highlight patterns that might lead to duplicate‑looking events.

4. How to avoid duplicates next time

To reduce the chance of this happening again:

• Pick one approach per calendar: either subscribe to a live calendar URL or periodically import a one‑time .ics — not both.
• Before importing, check if the calendar is already subscribed to that same source.
• For recurring events or complex schedules, ask the provider to send a single, well‑structured .ics instead of multiple overlapping files.
• If you manage the events system, run test imports in a separate calendar first.

Running the file through /fix before importing gives you a quick sanity check and a chance to catch obvious issues.

5. When to involve your IT or vendor

If you’re an event planner or communications lead and your calendar is a mess:

• Share the original .ics with your IT team or the vendor who generated it.
• Include any error messages from your calendar app.
• Optionally, send them the CorrectICS validation report or request ID from /fix.

This gives them a head start on fixing the template so future invitations don’t create duplicates for you or your attendees.