Microsoft 365 services in Japan and China have been fully restored after a widespread outage early Thursday left thousands of users unable to access critical applications. The disruption affected essential productivity tools like Outlook, Teams, OneDrive, and the AI assistant Copilot, causing significant interruptions to business and remote work across both major Asian markets.
Root Cause: A Routing Fault in Service Infrastructure
According to updates posted in Microsoft's admin center, the outage originated from a routing fault within the company's internal service infrastructure that handles traffic for Japan. This technical failure led to intermittent login failures, severely slow loading times, and degraded performance across apps for several hours. Microsoft engineers worked through the morning, implementing mitigation steps that involved rebalancing user traffic across backup systems to eventually stabilize the services.
Timeline and Details of the Disruption
The service disruption began around 12:00 am UTC (5:30 am IST). Users in Japan and China reported being completely locked out of Microsoft 365 applications. Many experienced repeated timeouts when trying to access cloud-based files or use the AI-powered features of Copilot. Microsoft confirmed that the impact was confined to the Asia-Pacific region and stated there was no evidence of a cyberattack. Initial assessments pointed to a routing misconfiguration that effectively isolated sections of otherwise functional infrastructure.
Microsoft provided successive updates as their mitigation efforts progressed. By approximately 12:10 PM Japan Standard Time (JST), engineers confirmed that traffic had been successfully rerouted across redundant systems and services were returning to normal operation.
Impact on Users and Final Recovery
While Microsoft confirmed there was no data loss or security breach, the downtime severely impacted organizations that rely on Microsoft's cloud ecosystem for daily operations. The most affected functions included:
- Workflows powered by the Copilot AI assistant.
- Email access via Outlook.
- File synchronization and sharing on OneDrive.
- Internal communication channels on Microsoft Teams.
In a final update shared on the microblogging platform X via the Microsoft 365 Status account, the company stated, "After an extended period of monitoring, we confirmed that our mitigating actions resolved impact for users." The post directed administrators to reference incident report MO1198797 in the admin center for more technical information.
