User impact: Users may have encountered performance issues with various Outlook clients.

More info: Users may have noticed that Outlook was consuming higher-than-normal system resources, affecting all Outlook connection methods, including the desktop client and Outlook on the web.

Resolution steps: This issue has been resolved; however, affected users may need to take specific actions to apply the changes:

Outlook Client and App users: Please restart the Outlook client or app. Desktop users may need to restart twice due to caching.

Outlook on the Web users: Refresh your session. If issues persist, clear your browser cache and refresh the session again.

Final status: After monitoring and addressing the issue with affected customers, we are confident that it has been fully resolved. For users still experiencing difficulties, please follow the guidance in the “Resolution Steps” section.

Scope of impact: The primary impact was on the Outlook client, though users on any connection method, including Outlook on the web and mobile apps, may have been affected.

Start time: Wednesday, October 9, 2024, at 12:15 PM UTC

End time: Thursday, October 10, 2024, at 5:05 PM UTC

Preliminary root cause: A separate service-impacting event caused an issue retrieving policy data. This caused Outlook users to experience high system memory usage, which resulted in poor performance and crashes.

Next Steps:
– We’re reviewing the root cause to implement measures to prevent similar issues in the future.

A preliminary Post-Incident Report will be provided within two business days, with a final report following within five business days.