How should I troubleshoot erroneous cancellation notices when scheduled meetings are updated with new attendees?

GARCIA, DAVID 5 Reputation points

Hello everyone: A particular department in my organization is experiencing this problem and I've been assigned to determine a cause and solution. Outlook/Exchange support is new technical territory for me, but I'm hoping to find some initial guidance on how to troubleshoot this.


Summary of Problem: Outlook Calendar meetings scheduled a year or more in advance, and with at least 60 invitees, are sending false cancelation notices to existing attendees whenever new attendees are added.



  • It’s January 31, 2024. It’s decided a board meeting will be scheduled for February 05, 2025.
  • Sixty-five attendees are scheduled to attend. Sometime later it’s decided more attendees will be invited.
  • As those new attendees are added to the meeting, attendees from the original sixty begin receiving cancellation notices.
  • This only happens with scheduled meetings with sixty or more attendees.


The last time this happened, the department was given a new email address. That was about a year ago and now the problem has returned. Any insight on how to troubleshoot this and what might be the underlying problem would be appreciated. Thank you.

Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
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  1. SokiGuo-MSFT 21,466 Reputation points Microsoft Vendor


    Do you choose to send notifications to all attendees after you update the meeting?

    What does it look like to receive a meeting cancellation notice? If there are screenshots, please be aware of overwriting your personal information.

    When you update a meeting, you will receive an email notification like the one below when you send an update to all attendees and may appear in deleted items. This behavior is a design dictate of Outlook.

    User's image

    In general, the meeting time will still be displayed normally in the Outlook calendar. If you don't want attendees to receive confusing meeting notifications, send updates only to attendees who are only added or removed.

    User's image

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