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How to migrate from Google Calendar to Exchange Online

If you want to start using Exchange Online as your primary calendar and migrate your data out of Google Calendar, follow these steps.

These instructions are also available in PDF format >


      ALERT:  Testing and experience has highlighted a few things to be aware of...

These issues will disappear over time as events become historic, but you may decide it's just easier to operate two calendars for a while, or to re-create your recurring meetings and those with other invitees in your Exchange Online calendar. You may want to seek advice from your Exchange Online migration team before you migrate your Google Calendar.

Identity crises

If your user ID is the same in both Google Calendars and Exchange Online (e.g., it can cause some conflicts when certain types of events are imported into Exchange Online, depending whether or not Google considers you to be the 'owner' or an 'invitee' of an event:

  • With 'simple' events, i.e. events you created that only involve you, things will work as expected.
  • With events that someone else invited you to, it may not always work as expected.
  • With events that you had created and invited others to, i.e. where Google considers you to be the 'owner' of the event, Exchange Online will treat 'Google you' and 'Exchange Online you' as two separate people. If you update such events in Exchange Online, it will only update your local copy, and not inform invitees of any changes, and Exchange Online won't notify you of the responses people make to the original Google Calendar event.

Errors when migrating recurring meetings

With recurring meetings, Google did not require an end date when the event was created, but Exchange Online does. This will cause an error when importing these types of event, and you’ll be prompted to enter an end date for the new Exchange Online calendar entry as each one gets imported.

To delete or not to delete?

Once you have migrated, it may appear to make sense to delete all your events from your Google Calendar so that people don’t continue to respond to your invitations, but if you do delete events that you had invited others to, two things will happen:

  • The other invitees will receive a meeting cancellation notification email. If you are deleting many entries (including historic events), you will not be popular with your colleagues!
  • Exchange Online, having added 'Exchange Online you' as an attendee of your own Google Calendar meeting, may either delete the meeting from your Exchange Online calendar without alerting you, or leave it marked as a cancelled meeting (i.e. it doesn’t work as expected).

Note: this must be done by the calendar owner; it can’t be done by someone with delegated admin rights.

  1. In a web browser, open your Google calendar.

  2. Under the My Calendars section in the sidebar, hover over the calendar you want to export and you will see the down arrow icon appear.


  3. Click the down arrow icon to open the sub-menu, and select Calendar Settings:


  4. Click the Export this calendar link to create a .ZIP file containing your calendar data, which typically saves to your Downloads folder.


  5. Locate the downloaded .ZIP file, and double-click to unzip it to extract the single .ics file.


  6. In a web browser, go to, and log in with your username and UIS Password. Click the Calendar tile:


  7. From the main navigation bar, click Add calendar and select From file in the drop-down menu:


  8. A pane will open in the left of the browser window. Use the Browse button to locate your calendar.ics file.

    You also have the option of choosing which of your Exchange Online calendars you want to add the data to (if you have more than one). Your primary Exchange Online calendar is called 'Calendar':


  9. Click the Save button at the top of the pane:


  10. Your Google calendar events will now be migrated to your Exchange Online calendar.
    Note: You may see alert pop-up windows during the import process, and will have to deal with these individually.

How to stop using Google Calendar

You can either stop sharing your calendar, to prevent people from responding to invitations, or delete it completely:

To stop sharing your Google Calendar:

  1. Under the My Calendars section in the sidebar, hover over the calendar you want to export and you will see the down arrow icon appear:


  2. Click the down arrow icon to open the sub-menu, and select Calendar Settings:


  3. Click the Share this Calendar tab:


  4. Untick the Share this calendar with others checkbox:


To delete your Google Calendar completely:

  1. Open your Google Calendar.

  2. In the top right, click the Settings icon: 15

  3. At the top of the page, click the Calendars tab.

  4. Click the name of the calendar to delete.

  5. At the bottom of the page, click Permanently delete this calendar.