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

12/08/2026 09:12:00 AM

NHS.net Connect Reference: INC46907040

Microsoft Reference: EX1441488

Issue Status: ONGOING

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: 27/08/2026 09:03:00 AM – The fix deployment has completed. Microsoft has determined that this fix is viable for all affected users but to see the impact remediated, users will need to run the following command: “Set-App -Identity “” -DefaultStateForUser Disabled -OrganizationApp -PrivateCatalog”. After running this command all users who previously installed add-ins may need to install them again. They are providing time for affected users to run this command and remediate impact before we consider this resolved.

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: Tuesday, September 1, 2026, at 6:30 PM UTC