Some users may be unable to access the default add-ins in Outlook

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may have been unable to access the default add-ins in Outlook. More info: This issue impacted both the Outlook desktop client and Outlook on the web. Some affected users found that the “My Templates” icon was missing from the Outlook ribbon, and others were unable to find templates in the AppData Microsoft Templates location, even though templates were known to exist and were still being used by non-impacted users. Some users also reported that the Viva Insights add-in was impacted by this event. Final status: We’ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following: https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange Scope of impact: Some users attempting to access or use the default add-ins within Outlook may have been impacted. Start time: Thursday, March 12, 2026, at 10:04 PM UTC End time: Friday, March 27, 2026, at 1:40 AM UTC Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. Next steps: - We’re reviewing how the impacting changes prevented users from accessing default add-ins so we can avoid similar issues in the future, as EWS is slated to be deprecated by October 2026. This is the final update for the event.

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're continuing our comparison of provided working and non-working user scenarios while conducting internal reproductions of impact to isolate potential issues contributing to this event. Due to multiple concurrent add-in functionality issues currently under investigation, this is taking additional time to complete. Meanwhile, we’re requesting additional trace logs from some users to aid this investigation. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Root cause: A recent REST API update prevents users from accessing default add-ins in Outlook. Next update by: Tuesday, March 31, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're continuing our comparison of the affected and non-affected users to correlate whether there are additional issues contributing to the impact, which will help us determine our next troubleshooting steps. Due to multiple ongoing add-in functionality issues, the investigation is taking time to complete. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Root cause: A recent REST API update prevents users from accessing default add-ins in Outlook. Next update by: Monday, March 30, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We rolled back this change for all impacted users and determine that while this resolved the issue for some users, others are still impacted. We're attempting to determine the difference between users that no longer experience this issue and those that are still impacted to determine a solution that completely remediates impact. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Root cause: A recent REST API update prevents users from accessing default add-ins in Outlook. Next update by: Saturday, March 28, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We've rolled back changes to the Representational State Transfer (REST) API for some users and confirmed that this addressed the default add-in issue with those affected users. We're rolling back this change for all impacted users and are monitoring as it saturates to confirm that impact is completely remediated. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Root cause: A recent REST API update prevents users from accessing default add-ins in Outlook. Next update by: Friday, March 27, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We've identified several recent changes which we suspect may be contributing to the impact, and we're developing a method by which we can verify whether reversing these changes is a viable mitigation strategy with a subset of affected users. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Thursday, March 26, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: Our analysis of internal system logs and service data is ongoing as we work to trace the underlying source of impact and determine our next steps. In parallel, we're reviewing recent updates and changes to the service to identify whether any may be contributing to impact. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Wednesday, March 25, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're furthering our investigation of our internal system logs and service data in conjunction with logs provided by affected users to isolate the source of impact to determine our next troubleshooting steps. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Thursday, March 26, 2026, at 1:00 AM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: Our analysis of system logs and service data is ongoing as we investigate potential sources of impact to assist our root cause and mitigation efforts. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Tuesday, March 24, 2026, at 1:00 AM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We’re continuing to analyze system logs and service data to isolate a potential root cause and determine next steps for mitigation. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Monday, March 23, 2026, at 7:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're continuing to analyze system logs and service data related to this issue to isolate a potential root cause and determine our next mitigative steps. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Monday, March 23, 2026, at 7:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're continuing our analysis of system logging and other service side data to understand why the default add-ins aren't enabled for user mailboxes as expected. In parallel, we're investigating whether this impact may be related to another event to assist in our understanding of the root cause. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Friday, March 20, 2026, at 9:00 PM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We're continuing to analyze our system logging to understand why the default add-ins are not enabling for user mailboxes as expected. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Friday, March 20, 2026, at 12:00 AM UTC

Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may be unable to access the default add-ins in Outlook. More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by non-impacted users. Some users also report that the Viva Insights add-in is also impacted by this event. Current status: We've identified an issue that's preventing users from accessing default add-ins that have been granted organizational access. We're analyzing system logging to isolate the source for the event, and so we can determine the next troubleshooting steps for remediating the impact. Scope of impact: Some users attempting to access or use the default add-ins within Outlook may be impacted. This information may be updated as our investigation continues. Next update by: Thursday, March 19, 2026, at 1:00 AM UTC