Microsoft 365 Alert – Service Degradation – Microsoft 365 suite – Users see duplicate meetings on their shared Exchange Online or Microsoft Teams calendar – RESOLVED

Announcements Arpan Das

18/09/2025 08:20:00 AM

NHSmail Reference: INC46632684

Microsoft Reference: MO1154713

Issue Status: RESOLVED

Issue Description: Users see duplicate meetings on their shared Exchange Online or Microsoft Teams calendar.

More info: Affected users can remove and re-add the offending calendar to remove duplicate items while we work to resolve this issue.

Final Update: 01/10/2025 07:50:00 AM – Microsoft confirmed the deployment of the change has completed and they’ve verified with a subset of affected users that the issue is resolved.

Scope of impact: Your organization is affected by this event, and users see duplicate meetings on their shared Exchange Online and Microsoft Teams calendar.

Root cause: A fix deployed for an alternate issue introduced a code error that’s causing meetings to duplicate.

Next steps: Microsoft are reviewing their protocols surrounding fix development and deployment to ensure similar issues are identified and corrected during testing so this doesn’t happen again.