Overview
- A large outage began Thursday evening and quickly spread to users in about 74 countries, with Downdetector recording roughly 130,000 Outlook problem reports at the peak.
- Microsoft says the problem stems from an unusually high number of servers becoming unavailable during automated health checks, which shifted load to remaining systems and caused connection failures.
- Engineers stopped deployments, restarted affected machines, routed traffic away from suspect servers and applied targeted configuration bypasses, but those steps delivered only limited and regionally uneven improvements overnight.
- The disruption has hit core Microsoft 365 services including Exchange/Outlook, Teams, SharePoint, Copilot, Defender XDR, admin portals and third‑party integrations, and it forced some governments and companies to request prioritized restoration or delay filings.
- Microsoft reports no sign of a cyberattack and says teams are pursuing alternative approaches to restore capacity, a reminder of the systemic risks from heavy reliance on centralized cloud infrastructure and of prior Azure/365 incidents this year.