How to sync iCal shared calendar with 'new' outlook (microsoft)

Question

Hi everyone — I’m having trouble with a calendar I subscribed to using an .ics URL from Apple iCloud. I added it in Outlook on the web (and can also see it in New Outlook for Windows) via Add calendar → Subscribe from web, but not all events appear

Can you offer any advise please?

Answer 1

Hi @Rebecca,

Welcome to Microsoft Q&A forum.   

Thank you for sharing your concern about the iCloud (.ics) calendar not showing all events after subscribing in Outlook. I understand how confusing it is when some items appear while others don’t, especially after adding the calendar correctly in Outlook on the web and seeing it sync to New Outlook for Windows.

Subscribed (.ICS) calendars refresh on a schedule that’s controlled by the server, so updates don’t appear instantly. Microsoft notes that refreshes can take up to 24 hours, even though the usual target is every 3–4 hours. At this time, there’s no option in Outlook to manually force or speed up the refresh.

For your reference: Import or subscribe to a calendar in Outlook.com or Outlook on the web.

To help you verify where the issue is coming from, here are a few steps you can try:

1. Check the ICS feed directly

Open the .ics link in a web browser. Search the page for the event’s title or date to confirm whether the missing event actually appears in the feed.

• If the event doesn’t show in the feed, the issue is with the source calendar (e.g., iCloud or the public calendar provider), not Outlook.

2. Validate the ICS link

Use an online ICS validator to check for formatting or data errors in the feed.

• If errors appear, the source calendar needs to be corrected (for example, by regenerating the public link or adjusting problematic events).
• If no errors are found, move to the next step.

3. Re‑add the calendar subscription

If the ICS file looks correct, remove the existing subscription from Outlook and add it again. After re‑subscribing, allow time for the next scheduled refresh cycle to run.

4. For time‑sensitive updates

If the missing event is urgent, you can temporarily upload the calendar as a file (.ics) instead of subscribing. This imports a static snapshot of the calendar, which allows the event to appear immediately.

Here are additional references you may find helpful:

• Share a calendar on iCloud.com
• Set up iCloud Calendars and Contacts in Outlook on your Windows computer

Please note that this information is being provided by the moderator solely for your convenience. The referenced sites are not managed or overseen by the moderator, and therefore we cannot guarantee the accuracy, security, or suitability of any software or content available there. We recommend reviewing all information carefully and ensuring you understand any associated risks before following suggestions from the provided link. 

 

If the issue continues, I recommend contacting your IT support team so they can review the calendar configuration. If further assistance is needed, they can also open a support ticket through the Microsoft 365 admin center.

 

I hope this information helps. Please try the steps and let me know whether they resolve the issue. If the problem persists, we can work together to find a solution.  

As other users will also search for information in this community, your vote can significantly help those with similar inquiries quickly locate the most relevant resources. 

Thank you for your kindness and for contributing to the forum.   

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