Overview

• The outage was traced to authentication and mailbox infrastructure faults that began late on July 9
• Microsoft’s first remediation attempt failed to resolve the issue, prompting engineers to correct the patch before redeploying it
• As of Thursday afternoon, the revised fix has reached most affected environments, though no full-recovery timeline has been provided
• Millions of users experienced login errors, license alerts and severe slowdowns, with some accounts inaccessible for more than 12 hours
• Core Microsoft 365 applications such as Teams, Skype and Xbox services remained operational throughout the incident