Microsoft 365 Alert – Service Degradation – Exchange Online – Some users may see unwanted add-ins appearing automatically across all Outlook clients – NEW

12/08/2026 09:12:00 AM

NHS.net Connect Reference: INC46907040

Microsoft Reference: EX1441488

Issue Status: OPEN

Issue Description: Some users may see unwanted add-ins appearing automatically across all Outlook clients.

More info: These add-ins are configured to be available to users by admins but aren’t expected to be automatically installed.

Current Update: 12/08/2026 09:12:00 AM – Microsoft has developed and begun deploying the fix to the affected environments. They are monitoring its progress to ensure it propagates successfully, and based on their current estimates, they expect deployment to complete by Wednesday, August 26, 2026. They will provide further resolution updates as they become available.

Scope of impact: Impact may occur for some users that may see unwanted add-ins appearing automatically across all Outlook clients. This section may be updated as the investigation progresses.

Root cause: A portion of the Exchange Online add-in sync pipeline isn’t processing add-in state information as expected. This is causing incorrect EnabledStatus values being returned and Outlook automatically displaying add-ins configured as Available, which is resulting in impact.

Next update by: Wednesday, August 12, 2026, at 6:30 PM UTC