Microsoft blames massive Microsoft 365 outage on maintenance bug

A massive Microsoft 365 and Azure outage occurred on July 23, 2026, beginning at 10:44 AM ET, primarily affecting services in the West US Azure region. The incident was caused by a bug in Microsoft's automated network maintenance system that incorrectly removed IP routes from more devices than intended, disrupting connectivity. Services including SharePoint, OneDrive, Teams, Power BI, and Microsoft Defender were impacted, with traffic rerouting and recovery efforts completed by 2:26 PM ET. Microsoft confirmed resolution of the incident and is conducting a full internal review of its maintenance processes.

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