Outlook ICS Calendar Sync Not Reflecting New Events from Shared Team Calendar

Question

We have a calendar app that our team uses within Microsoft Teams to manage scheduling and events.

The app provides an option to export the calendar using an ICS link, which we’ve added to Outlook using the “Add calendar from internet” option. When we do this, the existing events appear correctly in Outlook at the time of setup.

However, we’ve encountered a problem:

• New events added in the app after the ICS link is added do not appear in Outlook.

It seems that Outlook either does not auto-refresh internet calendars, or does so only infrequently and unpredictably.

There also appears to be no option in Outlook to manually refresh an ICS calendar once added.

We’re hoping to better understand the behavior here:

Is there any way to manually or programmatically force Outlook to refresh an ICS calendar?

Does Outlook support any refresh interval configuration for internet calendars?

Are there any known limitations or caching behaviors with ICS URLs in Outlook that we should be aware of?

Our goal is to ensure the calendar remains synchronized across platforms, especially for teams that primarily use Outlook.

Any guidance or suggestions would be greatly appreciated.

Thank you!

Answer 1

Dear Mayur Zinge

Good day! Thank you for reaching out to Microsoft Q&A Forum. 

I understand how important it is to have a shared calendar that synchronizes seamlessly across users, especially in a professional environment. I'll do my best to guide you through this issue.

By the way, just to clarify, when you mentioned “ICS,” did you mean iCalendar format?  If so, I regret to inform you that since iCalendar is a third-party application, we unfortunately do not have access or the ability to directly support it. I recommend reaching out to the administrator or support team of that application for the most accurate guidance.

To better understand your situation and provide tailored guidance, I’d appreciate it if you could help clarify a few key details:

-May I know what version of Outlook you have? What version of Outlook do I have? - Microsoft Support -Sharing a few screenshots of the problem would be very helpful in understanding the situation more clearly

The issue you are facing may be due to differences in how New and Classic Outlook handle ICS files and shared calendars. Here's a structured approach to resolve it:

1. Verify Calendar Sharing Method While ICS files are suitable for sharing static snapshots of a calendar, they do not reliably update or sync in real-time across devices. For better synchronization: -Open the calendar in the Outlook desktop app. -Right-click the calendar > Sharing Permissions, and verify appropriate permissions (e.g., Can View, Can Edit). -Use the Share Calendar option to grant access rather than exporting as .ics.
2. Remove and Reassign Calendar Rights: -For the problematic user, consider removing and reassigning the rights to the shared calendar. -Share the calendar again to ensure proper synchronization.
3. Try Re-syncing the Calendar: Another workaround is to remove and re-add the calendar in Outlook: -In New Outlook, go to the Calendar section. -Right-click the shared calendar and select Remove. In New Outlook, go to the Calendar section. Right-click the shared calendar and select Remove.
4. Consider a Microsoft 365 Group or Shared Mailbox. If your team requires dynamic collaboration: -Create a Microsoft 365 Group or a shared mailbox calendar. -These options offer real-time syncing for all members and are supported consistently across New and Classic Outlook.

We hope this information is helpful and sincerely appreciate your understanding. Please let us know if there’s anything further, we can do to support you

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