Overview
- Microsoft 365 services including SharePoint, Teams, Outlook, OneDrive and related Azure services were widely disrupted on Thursday, July 23 and users reported login failures, frozen cloud files and dropped meetings.
- Crowdsourced telemetry showed a sudden surge in complaints with Downdetector logging thousands of reports shortly after the outage began and SharePoint accounting for the majority of errors.
- Microsoft traced the disruption to a bug in an automated maintenance request system that removed IP routes from more devices than intended and disrupted traffic entering and leaving its West US region.
- Engineers reverted the faulty change hours after it began which restored network paths and allowed affected Microsoft 365 services to recover, and Microsoft says it will publish a post-incident review after completing its internal analysis.
- The outage highlighted enterprise risk from concentration on a single cloud provider, left some IT teams without visibility in the Admin Center, and prompted guidance for customers to check continuity and disaster recovery plans.