CorrectICS

Google Workspace to Fastmail Calendar Migration

Moving from Google Workspace to Fastmail sounds straightforward: export your calendar from Google, then import it into Fastmail.

Sometimes it really is that simple.

But if your calendar is old, large, or already passed through other systems, the migration can turn into a cleanup job fast.

If your file is already failing or producing strange results, go straight to /fix.

For a real-world example of this problem at scale, see: How We Repaired a 30-Year Google Workspace Calendar for Migration to Fastmail.

1. Basic Google Workspace to Fastmail migration flow

A clean migration usually looks like this:

  1. Export the calendar from Google Workspace / Google Calendar.
  2. Save the .ics file locally.
  3. In Fastmail Calendar, choose the option to import or add calendar data from a file.
  4. Import the file once.
  5. Check that event counts, recurring meetings, and timezones look right.

If you are only moving one small, recent calendar, that may be enough.

2. What to check before you import

Before importing, quickly sanity-check the export:

  • Is this the right calendar and not a combined export you did not mean to move?
  • Is the file unusually large?
  • Does the calendar include many years of history?
  • Has it already been migrated between systems before?
  • Do you rely on recurring meetings, alarms, or timezone-sensitive events?

Those details raise the odds that you are dealing with a file that needs repair, not just a basic import.

3. Common failure modes during the move

The most common problems in this migration are:

Duplicate events

This often happens when someone imports the same file multiple times or retries after a partial failure.

Related: ICS Import Created Duplicate Events – How to Clean It Up.

Recurring events behave strangely

Older recurring events can expand differently across calendar apps or bring along confusing history.

Wrong times or shifted events

Timezone handling is a frequent source of migration pain, especially with older exports.

Related: Fix ICS Timezone Errors (Events at the Wrong Time).

File import fails completely

The export may contain invalid fields, formatting issues, or complexity that Fastmail does not handle well in a normal import flow.

Related: ICS File Won’t Import? Fix Google Calendar and Outlook Errors.

4. When to stop and repair the ICS first

Do not keep importing the same file if you notice:

  • duplicate events appearing
  • missing events after import
  • recurring series breaking apart
  • old events shifting to the wrong time
  • unclear partial imports

Repeated retries usually make cleanup harder.

Instead:

  1. keep the original export
  2. validate the file
  3. repair it if needed
  4. import the repaired version once

That is the safest path if you care about preserving years of calendar history.

5. When CorrectICS helps

CorrectICS is a good fit for this migration when the .ics file is:

  • too large to trust without validation
  • showing duplicate, recurrence, or timezone problems
  • failing to import cleanly into Fastmail
  • coming from a long-lived Google Workspace calendar with years of history

Use it to:

  • inspect the export
  • catch structural issues
  • reduce repeated import attempts
  • get a repaired file when safe fixes are available

Start here: /fix.

6. Practical migration checklist

Use this short checklist before you call the migration done:

  • Export the correct Google Workspace calendar.
  • Keep a backup copy of the original .ics.
  • Import only once into Fastmail.
  • Verify a sample of:
    • recurring meetings
    • all-day events
    • historical events
    • timezone-sensitive appointments
  • If anything looks wrong, stop and repair the file before importing again.

If your migration already feels messy, read the broader troubleshooting page: Why calendar imports break after migration.

7. Next step

If the move is not going cleanly, treat the file like a migration artifact that may need repair.

Fix your .ics file in seconds

Upload an iCalendar file and get a clean, import-ready version for Google Calendar, Outlook, Apple Calendar, and Teams.

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