India, Nov. 13 -- A global outage affecting Microsoft's enterprise and consumer services stretched into several hours on Friday. The company described the impact on apps including Outlook, Teams, OneDrive and Office on the web as a "service degradation", while engineers tried implementing fix after fix. Fourteen hours later, Microsoft finally said it had started noticing "positive results for service stability and increased capacity", but the disruption was far from over.

The cause officially cited was that something in the system caused otherwise perfectly fine servers to start failing automated health checks, which meant the load was shifted to other servers. They also began to struggle as a result, leading to instability. While Micros...