Microsoft experienced a significant outage on July 23, 2026, due to a bug in its automated network maintenance request system. During routine maintenance isolating specific network paths in the West US Azure region, the system incorrectly marked additional network devices for maintenance, causing IP routes to be removed from more devices than intended. This removal disrupted network traffic between Microsoft's West US datacenter and its wide-area network, affecting multiple Microsoft 365 and Azure services. Microsoft engineers traced the problem to the maintenance change, initiated a rollback, and restored affected infrastructure by 2:26 PM ET, with full recovery by 3:41 PM ET. The incident is under a detailed internal review focusing on safety checks and automated maintenance processes.

The outage caused connectivity failures, increased latency, and service disruptions for numerous Microsoft 365 services including SharePoint Online, Microsoft Teams, OneDrive, and the Microsoft 365 Admin Center, as well as Azure services such as Azure App Service, Azure Kubernetes Service, Azure Cosmos DB, and others. Users experienced errors, degraded functionality, intermittent access, and delays in security-related services like Microsoft Defender. The disruption primarily affected customers accessing services through network infrastructure connected to the West US Azure region. The outage lasted several hours until the maintenance change was rolled back and services were restored.

Microsoft has resolved the outage by rolling back the faulty maintenance change and restoring network routes. The company is conducting a full internal review of the automated maintenance request system and safety checks to prevent recurrence. No immediate action is required from customers, but Microsoft initially advised reviewing business continuity and disaster recovery plans as a precaution. Customers should monitor official Microsoft communications for the forthcoming Post Incident Review and any additional guidance.