SAN PABLO CITY, Laguna | A widespread Microsoft service disruption affected businesses, government agencies and millions of users across several countries on Thursday, November 12, interrupting access to Outlook, Microsoft 365 and other cloud-based applications as the technology company struggled to restore normal operations.
The hours-long outage disrupted email communications and workplace applications, leaving users unable to access inboxes, send or receive messages, retrieve files and use various collaboration and administrative tools.
According to The Associated Press, Downdetector recorded nearly 130,000 reports of Outlook-related problems shortly after 1 p.m. Eastern time on Thursday. Reports later declined, but service interruptions continued across several regions, including parts of Asia.
Microsoft initially attributed the disruption to unusually high infrastructure loads across multiple regions. Its investigation found that several servers were failing automated health checks and becoming unavailable, placing additional pressure on the remaining operational infrastructure.
Attempts to restart and restore affected servers were initially unsuccessful, with some machines becoming unresponsive again after receiving traffic. Microsoft subsequently redirected connections to alternative pathways, isolated affected infrastructure and introduced traffic-management measures to ease pressure on its systems.
In its latest update available Friday, November 13, Microsoft reported improving service availability in Europe and North America, although some users continued experiencing intermittent problems. Japan remained comparatively more stable. The company also maintained an extended 48-hour email timeout window to help protect delayed messages while delivery backlogs were cleared.
The disruption extended beyond email services, affecting Microsoft Teams, SharePoint, Copilot, Microsoft Defender, Planner, Power BI, Intune and other business and administrative applications. Some Teams functions remained operational, while features dependent on Exchange Online experienced problems.
Government operations were also affected. Japan’s Deputy Chief Cabinet Secretary Masanao Ozaki confirmed that government information technology infrastructure had experienced disruptions. In the United Kingdom, reports also emerged of interruptions involving healthcare services, schools and government operations.
Microsoft said it had found no evidence of malicious activity associated with the incident and promised to release a detailed post-incident report explaining the root cause and measures to prevent similar disruptions. The company had not yet declared the incident fully resolved as of its latest published update.
The incident highlights the growing dependence of businesses and governments on centralized cloud infrastructure. Microsoft’s Office 365 service, introduced in June 2011 and renamed Microsoft 365 in 2020, has evolved into a broad platform encompassing email, document management, cloud storage, cybersecurity and workplace collaboration.
Its widespread adoption has made service interruptions particularly consequential for organizations that rely on the platform for daily operations. The latest disruption underscores the importance of maintaining alternative communication channels, backup systems and business continuity plans rather than relying exclusively on a single cloud service provider.
Edgardo Hernal started college at UP Diliman and received his BA in Economics from San Sebastian College, Manila, and Masters in Information Systems Management from Keller Graduate School of Management of DeVry University in Oak Brook, IL. He has 25 years of copy editing and management experience at Thomson West, a subsidiary of Thomson Reuters.
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